Estimation of Crystalline Cellulose Content of Plant Biomass using the Updegraff Method

Cellulose is the most abundant polymer on Earth generated by photosynthesis and the main load-bearing component of cell walls. The cell wall plays a ...

Estimation of Plant Biomass Lignin Content using Thioglycolic Acid (TGA)

Lignin is a natural polymer that is the second most abundant polymer on Earth after cellulose. Lignin is mainly deposited in plant secondary cell walls ...

Texas Tech University

Protein kinases play fundamental roles in plant development and environmental stress responses. Here, we identified the  () gene family, which encodes four leucine-rich repeat receptor-like protein kinases in Arabidopsis (). The four genes,  to , are clustered in the genome and highly conserved, but they have temporally and spatially distinct expression patterns. We employed Arabidopsis  knockout mutants and overexpression transgenics to examine SIF involvement during plant pathogen defense.  genes are rapidly induced by biotic or abiotic stresses, and SIF proteins localize to the plasma membrane. Simultaneous knockout of  and  led to improved plant salt tolerance, whereas  overexpression enhanced PAMP-triggered immunity and prompted basal plant defenses, significantly improving pathogen resistance. Furthermore,  overexpression plants exhibited up-regulated expression of the defense-related genes  and  as well as enhanced MPK3/MPK6 phosphorylation upon pathogen and elicitor treatments. The expression of the calcium signaling-related gene  also was enhanced in the -overexpressing lines upon pathogen inoculation but repressed in the  mutants. Bimolecular fluorescence complementation demonstrates that the BRI1-ASSOCIATED RECEPTOR KINASE1 protein is a coreceptor of the SIF2 kinase in the signal transduction pathway during pathogen invasion. These findings characterize a stress-responsive protein kinase family and illustrate how SIF2 modulates signal transduction for effective plant pathogenic defense.

STRESS INDUCED FACTOR 2, a Leucine-Rich Repeat Kinase Regulates Basal Plant Pathogen Defense.

As one of the largest subfamilies of the receptor-like protein kinases (RLKs) in plants, Leucine Rich Repeats-RLKs (LRR-RLKs) are involved in many critical biological processes including growth, development and stress responses in addition to various physiological roles. Arabidopsis contains 234 LRR-RLKs, and four members of Stress Induced Factor (SIF) subfamily (AtSIF1-AtSIF4) which are involved in abiotic and biotic stress responses. Herein, we aimed at identification and functional characterization of SIF subfamily in cultivated tetraploid cotton Gossypium hirsutum.

Genome-wide identification and characterization of LRR-RLKs reveal functional conservation of the SIF subfamily in cotton (Gossypium hirsutum).

Cellulose synthesis is precisely regulated by internal and external cues, and emerging evidence suggests that light regulates cellulose biosynthesis through specific light receptors. Recently, the blue light receptor CRYPTOCHROME 1 (CRY1) was shown to positively regulate secondary cell wall biosynthesis in Arabidopsis (). Here, we characterize the role of ,  (), another blue light receptor and well-known photoperiodic flowering time regulator, in cellulose biosynthesis. A phenotype suppression screen using a cellulose deficient mutant  (), which carries nonlethal point mutations in  () and , resulted in identification of the phenotype-restoring  () mutant. Next-generation mapping using the whole genome resequencing method identified the  locus as  was confirmed as the causal gene through observation of the  phenotype in an independent triple mutant  carrying a  T-DNA insertion mutant. Moreover, overexpression of  in  plants restored the  phenotype. The  mutants showed significant increases in cellulose content and  gene expression compared with that in wild-type Columbia-0 plants, suggesting a negative role of FKF1 in cellulose biosynthesis. Using genetic, molecular, and phenocopy and biochemical evidence, we have firmly established the role of FKF1 in regulation of cellulose biosynthesis. In addition,  expression analysis showed that diurnal expression patterns of s are FKF1 independent, whereas their circadian expression patterns are FKF1 dependent. Overall, our work establishes a role of FKF1 in the regulation of cell wall biosynthesis in Arabidopsis.

The Photoperiodic Flowering Time Regulator FKF1 Negatively Regulates Cellulose Biosynthesis.

A novel inducible secretion system mutation in Sorghum named Red root has been identified. The mutant plant root exudes pigmented compounds that enriches Actinobacteria in its rhizosphere compared to BTx623. Favorable plant-microbe interactions in the rhizosphere positively influence plant growth and stress tolerance. Sorghum bicolor, a staple biomass and food crop, has been shown to selectively recruit Gram-positive bacteria (Actinobacteria) in its rhizosphere under drought conditions to enhance stress tolerance. However, the genetic/biochemical mechanism underlying the selective enrichment of specific microbial phyla in the sorghum rhizosphere is poorly known due to the lack of available mutants with altered root secretion systems. Using a subset of sorghum ethyl methanesulfonate (EMS) mutant lines, we have isolated a novel Red root (RR) mutant with an increased accumulation and secretion of phenolic compounds in roots. Genetic analysis showed that RR is a single dominant mutation. We further investigated the effect of root-specific phenolic compounds on rhizosphere microbiome composition under well-watered and water-deficit conditions. The microbiome diversity analysis of the RR rhizosphere showed that Actinobacteria were enriched significantly under the well-watered condition but showed no significant change under the water-deficit condition. BTx623 rhizosphere showed a significant increase in Actinobacteria under the water-deficit condition. Overall, the rhizosphere of RR genotype retained a higher bacterial diversity and richness relative to the rhizosphere of BTx623, especially under water-deficit condition. Therefore, the RR mutant provides an excellent genetic resource for rhizosphere-microbiome interaction studies as well as to develop drought-tolerant lines. Identification of the RR gene and the molecular mechanism through which the mutant selectively enriches microbial populations in the rhizosphere will be useful in designing strategies for improving sorghum productivity and stress tolerance.

Ning Yuan

Fiber and Biopolymer Research Institute (FBRI),
Department of Plant and Soil Science

Texas Tech University

Estimation of Crystalline Cellulose Content of Plant Biomass using the Updegraff Method

Estimation of Plant Biomass Lignin Content using Thioglycolic Acid (TGA)

Ning Yuan

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Fiber and Biopolymer Research Institute (FBRI),Department of Plant and Soil Science

Texas Tech University

Estimation of Crystalline Cellulose Content of Plant Biomass using the Updegraff Method

Estimation of Plant Biomass Lignin Content using Thioglycolic Acid (TGA)

Fiber and Biopolymer Research Institute (FBRI),
Department of Plant and Soil Science