The authors would like to thank California Department of Food and Agriculture for funding of the project which led to the development of this protocol. CDFA SCB11019.

1. Plantio <ol><li> Preencha bandejas plugue (128 cela; 28 x 54 cm, com células 3 centímetros quadrados e 5 cm de profundidade) com mix plugue solo. Para ajudar no preenchimento uniforme de células compactar solo em cada bandeja usando uma bandeja de plugue vazio. </li><li> Sementes de alface Planta ¼ de polegada de profundidade 2-3 sementes por célula. Planta de todas as linhas experimentais em bandejas replicadas para fornecer tanto uma seca estressado e bandejas de controle para o julgamento de seca. </li><li> Coloque as bandejas de plug em uma bandeja de base sem buracos. </li><li> Bandejas de água e cubra com bandeja invertida ou cúpula de plástico. A germinação ocorre normalmente em 48-72 h. Após a germinação retire a tampa e mover bandejas em estufa. NOTA: Este protocolo também pode ser realizada em câmaras de crescimento. </li></ol> 2. Crescimento e plantas cuidados <ol><li> Bandejas de água, conforme necessário 1-4 semanas após a germinação, normalmente este é 2-3 vezes por semana, através do preenchimento de bandeja inferior e permitindo que o solo a ficar saturadas (~ 1 hr) raios de se sentar por período prolongados na água, pois isso pode impactar negativamente a saúde das plantas e desenvolvimento radicular e pode afetar a tela de seca. </li><li> Fertilize bandejas uma vez por semana com um solúvel 20-20-20 fertilizante comercial misturado a uma taxa de 1,5 colher de chá / gal. </li><li> Bandejas fina para uma planta por celulares 1-2 semanas após a germinação. </li></ol> 3. Início de estresse hídrico <ol><li> Quando as plantas são quatro semanas bandejas separadas em 2 grupos. Assunto um grupo ao estresse hídrico severo. Use as outras bandejas, bem regadas controles. Regue o grupo controle como no passo 2.1 durante todo o experimento. No início do estresse seca suspender fertilizar todas as bandejas para o resto da experiência. </li><li> O período de seca experimental ocorre ao longo de uma semana. No dia inicial do julgamento de estresse hídrico (Dia 0) preencher todas as bandejas inferiores com água e permitir que o solo nas bandejas de plug para se tornar totalmente saturado, em seguida, drenar a água da bandeja. Saturando o solo imediatamente antes do início do tele período de estresse vai ajudar a minimizar qualquer variação na umidade do solo entre as células individuais nas bandejas de ficha. </li></ol> 4. Realização da tela estresse hídrico básico com parâmetros a serem medidos NOTA: As seguintes etapas descrevem como coletar as três medidas fisiológicas que serão registrados ao longo de tela a seca enquanto que a Tabela 1 apresenta um cronograma das medidas tomadas em cada dia do período experimental seca-stress. <ol><li> Medir a Folha Relativa conteúdo de água (RWC) nos dias 0, 2, 4 do julgamento. <ol><li> Clipe de uma planta alface da bandeja e remover 2 folhas. </li><li> Perfure 3 discos de cada folha usando uma broca de cortiça # 9 (de ~ 1,6 cm de diâmetro). Combine socos folha como uma amostra. </li><li> Pese os discos de folhas, este é o valor do peso fresco (FW) utilizado para o cálculo RWC, em seguida, coloque os discos em uma placa de petri. </li><li> Adicione água destilada apenas o suficiente para a placa para todosow todos os discos de folha a flutuar. Isto é para hidratar completamente os discos de folha para reunir pesos túrgidas para análise RWC. Permitir que os discos de folha para flutuar durante 24 horas à temperatura ambiente. </li><li> Remover os discos foliares agora totalmente hidratados a partir das placas e secar suavemente a superfície exterior dos discos de folha com toalhas de papel antes da pesagem, os discos. Grave estes pesos como peso bombástico (TW) para o cálculo RWC. </li><li> Discos de folha no lugar um laboratório de papel limpe ou disco de papel de filtro numa placa de Petri aberta e seco em estufa a 55 ° C durante 24 horas. NOTA: O papel impede que os discos de folha de aderir à placa de Petri durante a secagem. </li><li> Pesar discos de folha seca e registre pesos como seca (MS) para o cálculo da RWC. </li><li> Calcule RWC usando a fórmula de Weatherley como descrito por Smart e Bingham 11,12. RWC = (FW-DW / TWDw) * 100 FW = peso fresco, TW = peso bombástico, DW = peso seco </li><li> Repita o passo 4.1 para cada germoplasma e tratamento no julgamento. </li></ol></li><li> Grave a planta murcha início uma vez por dia no 1º dia do julgamento estresse da seca e termina quando 100% das plantas estão murchas, normalmente 4 ou 5 dias. </li><li> Fase de recuperação e diferencial de crescimento <ol><li> No dia 6, concluir o período da seca-stress e as plantas estressadas entrar na fase de recuperação do julgamento. Encha as bandejas inferiores com água e deixe as bandejas sob estresse de molho por 24 horas antes de retomar o plano de rega padrão, passo 2.1, como as bandejas de controle. </li><li> Permitir que todas as plantas recuperar durante 10 dias. </li><li> Aos 10 dias após a seca-stress colher toda a parte acima do solo de cada planta e registrar o peso fresco. </li></ol></li></ol>

<ol>
	<li>Dijk, A. I. J. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Millennium+Drought+in+southeast+Australia+(2001&#8211;2009):+Natural+and+human+causes+and+implications+for+water+resources,+ecosystems,+economy,+and+society.">The Millennium Drought in southeast Australia (2001&#8211;2009): Natural and human causes and implications for water resources, ecosystems, economy, and society.</a> Water Resour. Res. 49, (2013).</li><li>Aghakouchak, A., Feldman, D., Stewardson, M. J., Saphores, J., Grant, S., Sanders, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Australia&#8217;s+Drought:+Lessons+for+California.">Australia&#8217;s Drought: Lessons for California.</a> Science. 343, 1430 (2014).</li><li>Tolomeo, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=California+Agricultural+Statistics+2012+Crop+Year.">California Agricultural Statistics 2012 Crop Year.</a> USDA National Agricultural Statistics Service Pacific Regional Office-California. , (2013).</li><li>Cavagnaro, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Climate+Change:+Challenges+and+Solutions+for+California+Agricultural+Landscapes.+White+paper+CEC-500-2005-189-SF.">Climate Change: Challenges and Solutions for California Agricultural Landscapes. White paper CEC-500-2005-189-SF.</a> California Climate Change Center. , (2005).</li><li>Lobell, D. B., Gourdji, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Influence+of+Climate+Change+on+Global+Crop+Productivity.">The Influence of Climate Change on Global Crop Productivity.</a> Plant Physiol. 160, 1686-1697 (2012).</li><li>Jackson, L. E., Stivers, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Root+distribution+of+lettuce+under+commercial+production:+implications+for+crop+uptake+of+nitrogen.">Root distribution of lettuce under commercial production: implications for crop uptake of nitrogen.</a> Biological Agriculture and Horticulture. 9, 273-293 (1993).</li><li>Jackson, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Root+architecture+in+cultivated+and+wild+lettuce+(Lactuca+spp).">Root architecture in cultivated and wild lettuce (Lactuca spp).</a> Plant. Cell and Environment. 18, 885-897 (1995).</li><li>Malcom, S., Marshall, E., Aillery, M., Heisey, P., Livingston, M., Day-Rubenstein, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Agricultural+Adaptation+to+a+Changing+Climate:+Economic+and+Environmental+Implications+Vary+by+U.S+Region.+USDA+Economic+Research+Service.">Agricultural Adaptation to a Changing Climate: Economic and Environmental Implications Vary by U.S Region. USDA Economic Research Service.</a> Economic Research Report Number. 136, (2012).</li><li>Chaves, M. M., Maroco, J. P., Pereira, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Understanding+plant+responses+to+drought-+from+genes+to+the+whole+plant.">Understanding plant responses to drought- from genes to the whole plant.</a> Funct. Plant Biol. 30, 239-264 (2003).</li><li>Ingram, J., Bartels, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Molecular+Basis+of+Dehydration+Tolerance+in+Plants.">The Molecular Basis of Dehydration Tolerance in Plants.</a> Annu. Rev. Plant Physiol. Plant Mol. Biol. 47, 377-403 (1996).</li><li>Weatherley, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+in+the+water+relations+of+the+cotton+plant.+I.+The+field+measurement+of+water+deficits+in+leaves.">Studies in the water relations of the cotton plant. I. The field measurement of water deficits in leaves.</a> New Phlytol. 49, 81-97 (1950).</li><li>Smart, R. E., Bingham, G. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+Estimates+of+Relative+Water+Content.">Rapid Estimates of Relative Water Content.</a> Plant Physiol. 53, 258-260 (1974).</li></ol>

The authors declare that they have no competing financial interests.

Considerações do número da amostra para a tela. O número de amostras necessárias deve ser baseada na utilização desejada dos dados a partir deste ecrã. Se os resultados de qualidade de publicação são desejados, recomenda-se colher 3 plantas individuais (3 repetições biológicas) de cada linha e realizar um mínimo de 2 repetições experimentais para dar pontos adequados para a análise estatística de qualidade. Se o resultado desejado é simplesmente para estr...

Water availability for irrigation has been a concern across much of the United States and globally for decades, but research into the response to drought-stress, along with other abiotic stresses, has lagged behind work in the areas of disease and insect resistance, at the industrial, academic, and governmental levels largely due to a lack of funding. Water availability for agriculture has historically been only an afterthought at the level of policy makers. Recently, due to several severe droughts in important agricultural production regions in both the United States and Australia1,2 fresh water availability has been thrust into the spotlight at both the national and international levels leading to many more resources being directed towards research into developing drought-tolerant cultivars of the major grain crops. While this shifting focus toward the development of drought-tolerant major crops is beneficial, like many areas of plant research specialty crops have largely been left behind. 
A severe drought is currently limiting vegetable production in California, the largest production region for Lettuce (Lactuca sativa L.) in the United States3. These short-term weather patterns coupled with legislative and judicial action along with long-term climate change4,5 have combined to reduce water available for agriculture in many of the most productive regions of California. Lettuce production in California represents a 1.5 billion dollar industry accounting for nearly 80% of lettuce production in the United States3. Leafy vegetables have high leaf water content and lettuce, in particular, has a shallow root system6,7 which leaves the crop vulnerable to water-stress. In lettuce, as in all crops the development of drought-tolerant varieties will become increasingly important as fresh water supplies for irrigation become more constrained8.
This protocol lays out a method by which an initial screen was performed on a large collection of lettuce germplasm in order to identify a pool of potentially drought-tolerant candidate lines for use in physiological, molecular, and genetic studies to identify specific drought-tolerance traits. These candidates can also be used directly as sources of drought-tolerance in breeding programs to improve water use efficiency in commercial cultivars. This protocol was developed specifically to address the challenges that arise during the course of any screen of an extensive germplasm collection, especially issues of space availability and labor. Also, the protocol as presented was developed for use in lettuce, but has been successfully adapted for use in the screening of a germplasm collection of spinach (Spinacia oleracea) for potential drought-tolerance and could be modified simply to screen any leafy vegetable crop. 
An important consideration before initiating a drought-tolerance screen is to understand what this method is and is not. This protocol is meant to represent a rapid method by which a large germplasm pool can be quickly and efficiently narrowed to a manageable number of candidate germplasm for use in more focused and thorough studies to identify individual tolerance traits. This protocol subjects the plants to a rapidly induced severe water-stress in contrast to a more natural slowly-induced moderate continuous drought-stress that would be observed under field conditions. The type of response induced within the plant during these two types of water-stress events (rapid dehydration versus natural drought) is not identical9 which could lead to the exclusion of some materials from future trials. These two stress events are not without overlap though10 and this protocol should serve as an effective way to identify potentially drought-tolerant germplasm contained within a large collection. This protocol alone should not be considered sufficient to identify with a high degree of certainty germplasm that contains durable drought-tolerance under field water-stress conditions, but it represents a significant step forward in the rapid screening of leafy green vegetables for potential drought-tolerance traits.

<table><tbody><tr><td>plug tray 128</td><td>T.O. Plastics&lt;br/&gt; Hummert International</td><td>11-8595-1</td><td>Any brand plug tray will work, but use the same style of trays for all trials.</td></tr><tr><td>lower tray (Display tray)</td><td>T.O. Plastics&lt;br/&gt; Hummert International</td><td>11-3305-1</td><td></td></tr><tr><td>plug/planting mix (Sunshine Mix #5)</td><td>Sunshine&lt;br/&gt; Hummert International</td><td>10-0467-1</td><td>A different mix may need to be substituted if adapting this protocol to a different crop.&amp;nbsp; Sunshine mix #4 was used in spinach trials.</td></tr><tr><td>fertilizer (20-20-20)</td><td>Jack&#039;s: Professional water-soluble fertilizer&lt;br/&gt; Hummert International</td><td>07-5915-1</td><td>Any fertilizer can be used, adjust type as needed for adapting this protocol to specific crop needs.</td></tr></tbody></table>

semi-high throughput screening for potential drought-tolerance in lettuce (lactuca sativa) germplasm collections

This protocol describes a method by which a large collection of the leafy green vegetable lettuce (Lactuca sativa L.) germplasm was screened for likely drought-tolerance traits. Fresh water availability for agricultural use is a growing concern across the United States as well as many regions of the world. Short-term drought events along with regulatory intervention in the regulation of water availability coupled with the looming threat of long-term climate shifts that may lead to reduced precipitation in many important agricultural regions has increased the need to hasten the development of crops adapted for improved water use efficiency in order to maintain or expand production in the coming years. This protocol is not meant as a step-by-step guide to identifying at either the physiological or molecular level drought-tolerance traits in lettuce, but rather is a method developed and refined through the screening of thousands of different lettuce varieties. The nature of this screen is based in part on the streamlined measurements focusing on only three water-stress indicators: leaf relative water content, wilt, and differential plant growth following drought-stress. The purpose of rapidly screening a large germplasm collection is to narrow the candidate pool to a point in which more intensive physiological, molecular, and genetic methods can be applied to identify specific drought-tolerant traits in either the lab or field. Candidates can also be directly incorporated into breeding programs as a source of drought-tolerance traits.

Ao realizar uma tela grande, a fim de segregar uma população experimental pelo traço desejado, no caso de este protocolo de resposta seca-stress, os dados gerados será correspondentemente ser variada de muito susceptível a salientar provável tolerante a secas e todos os pontos entre eles. A Figura 1 contém gráficos que representam o tipo de resultado que pode ser esperado a partir deste protocolo. Cultivares representativos de três tipos de alface (alface romana (cos), alface crespa, e Butterhe...

Watch this Scientific Journal Video about Semi-High Throughput Screening for Potential Drought-tolerance in Lettuce Lactuca sativa Germplasm Collections at JoVE.com

Triagem de rendimento semi-alto para potencial tolerância à seca em coleções de germoplasma de Lactuca sativa de alface | Meio Ambiente | Vídeo

Semi-High Throughput Screening for Potential Drought-tolerance in Lettuce Lactuca sativa Germplasm Collections

This protocol was developed to screen a large germplasm collection of the leafy vegetable lettuce (Lactuca sativa L.) for drought-tolerance, in order to identify a small candidate pool of lettuce for use in physiological, molecular, and genetic studies to identify underlying drought-tolerance traits along with breeding programs.

Screening Semi-High Throughput para o Potencial tolerância à seca em alface ( Lactuca sativa) Germoplasma Colecções

This protocol describes a method by which a large collection of the leafy green vegetable lettuce (Lactuca sativa L.) germplasm was screened for likely ...

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Semi-High Throughput Screening for Potential Drought-tolerance in Lettuce (Lactuca sativa) Germplasm Collections

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9.0K visualizações.  United States Department of Agriculture. This protocol was developed to screen a large germplasm collection of the leafy vegetable lettuce (Lactuca sativa L.) for drought-tolerance, in order to identify a small candidate pool of lettuce for use in physiological, molecular, and genetic studies to identify underlying drought-tolerance traits along with breeding programs.

Vídeo: Semi-High Throughput Screening for Potential Drought-tolerance in Lettuce Lactuca sativa Germplasm Collections

High and Low Throughput Screens with Root-knot Nematodes Meloidogyne spp.

Root-knot nematodes (genus Meloidogyne) are obligate plant parasites. They are extremely polyphagous and considered one of the most economically important plant parasitic nematodes. The microscopic second-stage juvenile (J2), molted once in the egg, is the infective stage. The J2s hatch from the eggs, move freely in the soil within a film of water, and locate root tips of suitable plant species. After penetrating the plant root, they migrate towards the vascular cylinder where they establish a feeding site and initiate feeding using their stylets. The multicellular feeding site is comprised of several enlarged multinuclear cells called 'giant cells' which are formed from cells that underwent karyokinesis (repeated mitosis) without cytokinesis. Neighboring pericycle cells divide and enlarge in size giving rise to a typical gall or root knot, the characteristic symptom of root-knot nematode infection. Once feeding is initiated, J2s become sedentary and undergo three additional molts to become adults. The adult female lays 150-250 eggs in a gelatinous matrix on or below the surface of the root. From the eggs new infective J2s hatch and start a new cycle. The root-knot nematode life cycle is completed in 4-6 weeks at 26-28&deg;C.
Here we present the traditional protocol to infect plants, grown in pots, with root-knot nematodes and two methods for high-throughput assays. The first high-throughput method is used for plants with small seeds such as tomato while the second is for plants with large seeds such as cowpea and common bean. Large seeds support extended seedling growth with minimal nutrient supplement. The first high throughput assay utilizes seedlings grown in sand in trays while in the second assay plants are grown in pouches in the absence of soil. The seedling growth pouch is made of a 15.5 x 12.5cm paper wick, folded at the top to form a 2-cm-deep trough in which the seed or seedling is placed. The paper wick is contained inside a transparent plastic pouch. These growth pouches allow direct observation of nematode infection symptoms, galling of roots and egg mass production, under the surface of a transparent pouch. Both methods allow the use of the screened plants, after phenotyping, for crossing or seed production. An additional advantage of the use of growth pouches is the small space requirement because pouches are stored in plastic hanging folders arranged in racks.

High and Low Throughput Screens with Root-knot Nematodes Meloidogyne spp.

Two distinct methods to screen plants with root-knot nematodes are described. The described approaches include high-throughput screens with nematodes in a nondestructive manner facilitating the use of these plants in breeding programs.

Alta e Baixa Screens rendimento com galhas-Nematóides Meloidogyne spp.</em

Root-knot nematodes (genus Meloidogyne) are obligate plant parasites. They are extremely polyphagous and considered one of the most economically important ...

Imunologia e Infecção

A Flexible Low Cost Hydroponic System for Assessing Plant Responses to Small Molecules in Sterile Conditions

A wide range of studies in plant biology are performed using hydroponic cultures. In this work, an in vitro hydroponic growth system designed for assessing plant responses to chemicals and other substances of interest is presented. This system is highly efficient in obtaining homogeneous and healthy seedlings of the C3 and C4 model species Arabidopsis thaliana and Setaria viridis, respectively. The sterile cultivation avoids algae and microorganism contamination, which are known limiting factors for plant normal growth and development in hydroponics. In addition, this system is scalable, enabling the harvest of plant material on a large scale with minor mechanical damage, as well as the harvest of individual parts of a plant if desired. A detailed protocol demonstrating that this system has an easy and low-cost assembly, as it uses pipette racks as the main platform for growing plants, is provided. The feasibility of this system was validated using Arabidopsis seedlings to assess the effect of the drug AZD-8055, a chemical inhibitor of the target of rapamycin (TOR) kinase. TOR inhibition was efficiently detected as early as 30 min after an AZD-8055 treatment in roots and shoots. Furthermore, AZD-8055-treated plants displayed the expected starch-excess phenotype. We proposed this hydroponic system as an ideal method for plant researchers aiming to monitor the action of plant inducers or inhibitors, as well as to assess metabolic fluxes using isotope-labeling compounds which, in general, requires the use of expensive reagents.

A simple, versatile, and low-cost in vitro hydroponic system was successfully optimized, enabling large-scale experiments under sterile conditions. This system facilitates the application of chemicals in a solution and their efficient absorption by roots for molecular, biochemical, and physiological studies.

Um flexível baixo custo sistema hidropônico para avaliar as respostas de planta para pequenas moléculas em condições estéreis

A wide range of studies in plant biology are performed using hydroponic cultures. In this work, an in vitro hydroponic growth system designed for ...

Ambiente

Optimizing the Use of a Liquid Handling Robot to Conduct a High Throughput Forward Chemical Genetics Screen of Arabidopsis thaliana

Chemical genetics is increasingly being employed to decode traits in plants that may be recalcitrant to traditional genetics due to gene redundancy or lethality. However, the probability of a synthetic small molecule being bioactive is low; therefore, thousands of molecules must be tested in order to find those of interest. Liquid handling robotics systems are designed to handle large numbers of samples, increasing the speed with which a chemical library can be screened in addition to minimizing/standardizing error. To achieve a high-throughput forward chemical genetics screen of a library of 50,000 small molecules on Arabidopsis thaliana (Arabidopsis), protocols using a bench-top multichannel liquid handling robot were developed that require minimal technician involvement. With these protocols, 3,271 small molecules were discovered that caused visible phenotypic alterations. 1,563 compounds induced short roots, 1,148 compounds altered coloration, 383 compounds caused root hair and other, non-categorized, alterations, and 177 compounds inhibited germination.

Optimizing the Use of a Liquid Handling Robot to Conduct a High Throughput Forward Chemical Genetics Screen of Arabidopsis thaliana

A high throughput screen of synthetic small molecules was conducted on the model plant species, Arabidopsis thaliana. This protocol, developed for a liquid handling robot, increases the speed of forward chemical genetics screens, accelerating the discovery of novel small molecules affecting plant physiology.

Otimizando o uso de um robô de manipulação líquidos para conduzir a uma alta taxa de transferência para a frente química genética tela de Arabidopsis thaliana

Chemical genetics is increasingly being employed to decode traits in plants that may be recalcitrant to traditional genetics due to gene redundancy or ...

Bioengenharia

High-Throughput Identification of Resistance to Pseudomonas syringae pv. Tomato in Tomato using Seedling Flood Assay

Tomato is an agronomically important crop that can be infected by Pseudomonas syringae, a Gram-negative bacterium, resulting in bacterial speck disease. The tomato-P. syringae pv. tomato pathosystem is widely used to dissect the genetic basis of plant innate responses and disease resistance. While disease was successfully managed for many decades through the introduction of the Pto/Prf gene cluster from Solanum pimpinellifolium into cultivated tomato, race 1 strains of P. syringae have evolved to overcome resistance conferred by the Pto/Prf gene cluster and occur worldwide.
Wild tomato species are important reservoirs of natural diversity in pathogen recognition, because they evolved in diverse environments with different pathogen pressures. In typical screens for disease resistance in wild tomato, adult plants are used, which can limit the number of plants that can be screened due to their extended growth time and greater growth space requirements. We developed a method to screen 10-day-old tomato seedlings for resistance, which minimizes plant growth time and growth chamber space, allows a rapid turnover of plants, and allows large sample sizes to be tested. Seedling outcomes of survival or death can be treated as discrete phenotypes or on a resistance scale defined by amount of new growth in surviving seedlings after flooding. This method has been optimized to screen 10-day-old tomato seedlings for resistance to two P. syringae strains and can easily be adapted to other P. syringae strains.

High-Throughput Identification of Resistance to Pseudomonas syringae pv. Tomato in Tomato using Seedling Flood Assay

The seedling flood assay facilitates rapid screening of wild tomato accessions for the resistance to the Pseudomonas syringae bacterium. This assay, used in conjunction with the seedling bacterial growth assay, can assist in further characterizing the underlying resistance to the bacterium, and can be used to screen mapping populations to determine the genetic basis of resistance.

Identificação de alta duração da resistência a Pseudomonas syringae pv. Tomate no Tomate usando Ensaio de Inundação de Mudas

Tomato is an agronomically important crop that can be infected by Pseudomonas syringae, a Gram-negative bacterium, resulting in bacterial speck disease. ...

Identification of Novel Regulators of Plant Transpiration by Large-Scale Thermal Imaging Screening in Helianthus Annuus

Plant adaptation to biotic and abiotic stresses is governed by a variety of factors, among which the regulation of stomatal aperture in response to water deficit or pathogens plays a crucial role. Identifying small molecules that regulate stomatal movement can therefore contribute to understanding the physiological basis by which plants adapt to their environment. Large-scale screening approaches that have been used to identify regulators of stomatal movement have potential limitations: some rely heavily on the abscisic acid (ABA) hormone signaling pathway, therefore excluding ABA-independent mechanisms, while others rely on the observation of indirect, long-term physiological effects such as plant growth and development. The screening method presented here allows the large-scale treatment of plants with a library of chemicals coupled with a direct quantification of their transpiration by thermal imaging. Since evaporation of water through transpiration results in leaf surface cooling, thermal imaging provides a non-invasive approach to investigate changes in stomatal conductance over time. In this protocol, Helianthus annuus seedlings are grown hydroponically and then treated by root feeding, in which the primary root is cut and dipped into the chemical being tested. Thermal imaging followed by statistical analysis of cotyledonary temperature changes over time allows for the identification of bioactive molecules modulating stomatal aperture. Our proof-of-concept experiments demonstrate that a chemical can be carried from the cut root to the cotyledon of the sunflower seedling within 10 minutes. In addition, when plants are treated with ABA as a positive control, an increase in leaf surface temperature can be detected within minutes. Our method thus allows the efficient and rapid identification of novel molecules regulating stomatal aperture.

Identification of Novel Regulators of Plant Transpiration by Large-Scale Thermal Imaging Screening in Helianthus Annuus

We provide a method for identifying modulators of foliar transpiration by large-scale screening of a compound library.

Identificação de novos reguladores de transpiração vegetal por triagem de imagens térmicas em larga escala em Helianthus Annuus

Plant adaptation to biotic and abiotic stresses is governed by a variety of factors, among which the regulation of stomatal aperture in response to water ...

Biologia

Screening of Tobacco Genotypes for Phytophthora nicotianae Resistance

Black shank, caused by the oomycetes Phytophthora nicotianae, is destructive to tobacco, and this pathogen is highly pathogenic to many solanaceous crops. P. nicotianae is well adapted to high temperatures; therefore, research on this pathogen is gaining importance in agriculture worldwide because of global warming. P. nicotianae-resistant varieties of tobacco plants are commonly screened by inoculation with oat grains colonized by P. nicotianae and monitoring for the disease symptoms. However, it is difficult to quantify the inoculation intensity since accurate inoculation is crucial in this case. This study aimed to develop an efficient and reliable method for evaluating the resistance of tobacco to infection with P. nicotianae. This method has been successfully used to identify resistant varieties, and the inoculation efficiency was confirmed by real-time PCR. The resistance evaluation method presented in this study is efficient and practical for precision breeding, as well as molecular mechanism research.

Screening of Tobacco Genotypes for Phytophthora nicotianae Resistance

Here, a protocol is presented for the efficient and accurate screening of tobacco genotypes for Phytophthora nicotianae resistance in seedlings. This is a practical approach for precision breeding, as well as molecular mechanism research.

Triagem de Genótipos de Tabaco para Resistência de Phytophthora nicotianae

Black shank, caused by the oomycetes Phytophthora nicotianae, is destructive to tobacco, and this pathogen is highly pathogenic to many solanaceous crops. ...

High-Throughput Analysis of Non-Photochemical Quenching in Crops Using Pulse Amplitude Modulated Chlorophyll Fluorometry

Photosynthesis is not optimized in modern crop varieties, and therefore provides an opportunity for improvement. Speeding up the relaxation of non-photochemical quenching (NPQ) has proven to be an effective strategy to increase photosynthetic performance. However, the potential to breed for improved NPQ and a complete understanding of the genetic basis of NPQ relaxation is lacking due to limitations of oversampling and data collection from field-grown crop plants. Building on previous reports, we present a high-throughput assay for analysis of NPQ relaxation rates in Glycine max (soybean) using pulse amplitude modulated (PAM) chlorophyll fluorometry. Leaf disks are sampled from field-grown soybeans before transportation to a laboratory where NPQ relaxation is measured in a closed PAM-fluorometer. NPQ relaxation parameters are calculated by fitting a bi-exponential function to the measured NPQ values following a transition from high to low light. Using this method, it is possible to test hundreds of genotypes within a day. The procedure has the potential to screen mutant and diversity panels for variation in NPQ relaxation, and can therefore be applied to both fundamental and applied research questions.

The protocol introduces a high-throughput method for measuring the relaxation of non-photochemical quenching by pulse amplitude modulated chlorophyll fluorometry. The method is applied to field-grown Glycine max and can be adapted to other species to screen for genetic diversity or breeding populations.

Análise de alta produtividade da extinção não fotoquímica nas culturas usando fluorometria modulada de clorofila modulada de pulso

Photosynthesis is not optimized in modern crop varieties, and therefore provides an opportunity for improvement. Speeding up the relaxation of ...

Um método aprimorado para medir os perfis de hidratação do pólen em Arabidopsis thaliana

A High-Resolution, Single-Grain, In Vivo Pollen Hydration Bioassay for Arabidopsis thaliana

Sexual reproduction in flowering plants requires initial interaction between the pollen grain and the stigmatic surface, where a molecular dialog is established between the interacting partners. Studies across a range of species have revealed that a series of molecular checkpoints regulate the pollen-stigma interaction to ensure that only compatible, generally intraspecific pollen is successful in effecting fertilization. In species that possess a 'dry stigma', such as the model plant Arabidopsis thaliana, the first post-pollination, prezygotic compatibility checkpoint is the establishment of pollen hydration. 
This phase of pollination is tightly regulated, whereby signals from the pollen grain elicit the release of water from the stigma, thus permitting pollen hydration. The ability to accurately measure and track pollen hydration over time is key to the design of experiments directed at understanding the regulation of this critical step in reproduction. Published protocols frequently utilize flowers that have been excised from the parent plant, maintained on liquid or solid media, and bulk pollinated. 
This paper describes a noninvasive, in vivo pollination bioassay that permits minute-by-minute hydration tracking of individual A. thaliana pollen grains at high resolution. The assay is highly reproducible, able to detect very subtle variations of pollen hydration profiles, and thus is suitable for the analysis of mutants that affect pathways regulating pollination. Although the protocol is lengthier than those described for bulk pollinations, the precision and reproducibility it provides, along with its in vivo nature, make it ideal for the detailed dissection of pollination phenotypes.

Autor em destaque: Um bioensaio de hidratação de pólen in vivo de alta resolução, grão único para Arabidopsis thaliana  

An improved method to measure pollen hydration profiles in Arabidopsis thaliana is described here. The new method offers higher resolution, is noninvasive, and is highly reproducible. The protocol represents a new tool for a finer dissection of the processes that regulate the early stages of pollination.

Bioensaio de Hidratação Polínica In Vivo de Grão Único de Alta Resolução para Arabidopsis thaliana

Sexual reproduction in flowering plants requires initial interaction between the pollen grain and the stigmatic surface, where a molecular dialog is ...

Screening Semi-High Throughput para o Potencial tolerância à seca em alface ( Lactuca sativa) Germoplasma Colecções

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Bioensaio de Hidratação Polínica In Vivo de Grão Único de Alta Resolução para Arabidopsis thaliana

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Bioensaio de Hidratação Polínica In Vivo de Grão Único de Alta Resolução para Arabidopsis thaliana