Agrobacterium tumefaciens and Agrobacterium rhizogenes-Mediated Transformation of Potato and the Promoter Activity of a Suberin Gene by GUS Staining

Summary

Here, we present two protocols to transform potato plants. The Agrobacterium tumefaciens transformation leads to a complete transgenic plant while the Agrobacterium rhizogenes produces transgenic hairy roots in a wild type shoot that can be self-propagated. We then detect promoter activity by GUS staining in the transformed roots.

Abstract

Agrobacterium sp. is one of the most widely used methods to obtain transgenic plants as it has the ability to transfer and integrate its own T-DNA into the plant's genome. Here, we present two transformation systems to genetically modify potato (Solanum tuberosum) plants. In A. tumefaciens transformation, leaves are infected, the transformed cells are selected and a new complete transformed plant is regenerated using phytohormones in 18 weeks. In A. rhizogenes transformation, stems are infected by injecting the bacteria with a needle, the new emerged transformed hairy roots are detected using a red fluorescent marker and the non-transformed roots are removed. In 5-6 weeks, the resulting plant is a composite of a wild type shoot with fully developed transformed hairy roots. To increase the biomass, the transformed hairy roots can be excised and self-propagated. We applied both Agrobacterium-mediated transformation methods to obtain roots expressing the GUS reporter gene driven by a suberin biosynthetic gene promoter. The GUS staining procedure is provided and allows the cell localization of the promoter induction. In both methods, the transformed potato roots showed GUS staining in the suberized endodermis and exodermis, and additionally, in A. rhizogenes transformed roots the GUS activity was also detected in the emergence of lateral roots. These results suggest that A. rhizogenes can be a fast alternative tool to study the genes that are expressed in roots.

Introduction

Aside from economic interest, the generation of transgenic plants has its own relevance in research to demonstrate the ultimate function of genes and to better understand plant physiology and development. The most widely used method for plant DNA insertion is Agrobacterium-mediated transformation. Agrobacterium tumefaciens is able to generate crown galls in the infected tissue of many plant species by the action of its tumour-inducing (Ti) plasmid. The plasmid contains a T-DNA region with a set of genes that will be integrated in the plant genome and induce tissue dedifferentiation^1,2. The ex....

Protocol

The A. rhizogenes transformation protocol was adapted and modified from Horn et al.⁷ and the genotype tested was S. tuberosum ssp. tuberosum (cv. Désirée). The A. tumefaciens transformation protocol was adapted and modified from Banerjee et al.²² and the genotypes tested were S. tuberosum ssp. tuberosum (cv. Désirée) and S. tuberosum ssp. andigena. The main steps of both procedures a.......

Discussion

In potato, the most common system to obtain stable complete transgenic plants uses the transformation by Agrobacterium tumefaciens strains that require organogenesis using exogenous phytohormones. Although the Agrobacterium based protocols has the potential to integrate non-T-DNA vector sequence²⁵, this methodology is still the easiest and less expensive available to transform potato plants. During last years, the interest in A. rhizogenes-mediated transformation has got.......

Materials

Name	Company	Catalog Number	Comments
Acetone	Panreac	1.310.071.21
Acetosyringone	Acros	115540050
Aquarium pump	Prodac	MP350
Autoclave	Ragpa Strelimatic
Bacteriological agar	Lab Conda	1800
BAP	Duchefa	B0904
Beef extract	Lab Conda	1700
Plant growing cabinet	Nuaire
Carbenicillin	Duchefa	C0109
Cefotaxime sodium	Duchefa	C0111
DMSO	Merck	1029310161
Ecotron infors	HT	29378
Ethanol	Merck	1,009,831,011
Falcon tube	Control tecnica	CFT011500
Ferricyanate	Sigma	101001081
Ferrocyanate	Sigma	100979088
Flask (8.06 cm diameter and 11.3 cm height) and plastic lid for in vitro culture	Apiglass	ref16
GA3	Sigma	G7645
Gamborg B5 media	Duchefa	G0210
Gelrite	Duchefa	G1101
Glucosa	Sigma	G5767
Kanamycin	Sigma	K1377
Leukopor tape	BSN Leukopor	BDF47467
Lupe	Wild-Heerbrugg	M420
Magnetic shaker	Agimatic	7000243
MES hydrate	Sigma	M2933-25G
MgSO4	Panreac	131404
Microscope	Olympus
Minufugue centrifugue 5415R	Eppendorf
Murashige and Skoog media	Duchefa	M0254.0050
Na2HPO4	Panreac	131679
NAA	Duchefa	N0903
NaCl	Panreac	131659
NaH2PO4	Sigma	58282
NightSea Stereo	SFA Moonting Adapter
Parafilm	Anorsa	PRFL-001-001
Peptone	Lab Conda	1616
Petri dishes (90 x 14)	Anorsa	200200
pHmetre	Crison
Phytotron	Inkoa	RFTI-R5485
Plant Agar	Duchefa	P1001
Refrigeratot	Liebherr Medline
Rifampicin	Duchefa	R0146
Spectinomycin	Sigma	59007
Spectrophotometer	Shimadzu
Square plates (120 x 120)	Deltalab	200204
Streptomycin	Sigma	S6501
Sucrose	Panreac	131621
Surgical blades	Swann-Morton	201
Surgical needle	NIPRO	015/0204
Triptone	Lab Conda	1612
Triton	Serva	37240
Unimax 1010 shaker	Heidolph
Vacuum	Dinko
x-GlcA (5-Bromo-4-chloro-3-indoxyl-beta-D-glucuronic acid, sodium salt anhydrous)	Biosynth	B-7398
Yeast extract	Lab Conda	1702.00
Zeatin riboside	Sigma	1001042850