Genotypic background of the recipient plant is crucial for conferring RB gene mediated late blight resistance in potato

Rajesh K Shandil,Swarup K Chakrabarti,Bir Pal Singh,Surinder K Kaushik,Arvind K Bhatt,Nitya Nand Sharma,Sanjeev Sharma,S Sundaresha

doi:10.1186/s12863-017-0490-x

Rajesh K Shandil, Swarup K Chakrabarti + Show 6 more

Open Access

https://doi.org/10.1186/s12863-017-0490-x

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Abstract

BackgroundLate blight, caused by oomycetes pathogen Phytophthora infestans (Mont.) de Bary, is the most devastating potato disease in the world. RB gene from Solanum bulbocastanum has been shown to impart broad spectrum resistance against P. infestans races. In this study Katahdin transgenic event SP951 was used as male parent to cross with the popular Indian potato cultivars viz., Kufri Bahar (KB) and Kufri Jyoti (KJ) to enhance the late blight resistance.ResultsPopulations of 271 F1seedlings from the crosses KB × SP951 (87) and KJ × SP951 (184) were screened for inheritance of RB transgene through PCR and bioassay. Disease response based on AUDPC of different hybrid lines varied from immunity to complete susceptibility. High degree of resistance (<25% infection) was observed in KJ × SP951 derived seedlings (85.2%), whereas level of resistance in KB × SP951 (36.4% infection) derived seedlings was of low order.ConclusionThis study provides valuable genetic materials for development of potentially durable late blight resistant potato varieties. Besides, it also corroborates the fact that efficacy of R gene is not solely dependent on its presence in the variety but largely depends on the genetic background of the recipient genotype.

Highlights

Late blight, caused by oomycetes pathogen Phytophthora infestans (Mont.) de Bary, is the most devastating potato disease in the world
Molecular analysis of F1seedlings When Kufri Bahar and Kufri Jyoti cultivars of potato were crossed with Katahdin transgenic event R gene from Solanum bulbocastanum (RB) transgenic Katahdin event (SP951) (RBtransgenic line), 271 F1seedlings (87 of KB× SP951 and 184 of KJ × SP951) were obtained and were tested for RB gene integration
Stability and inheritance of RB gene in F1 seedlings were confirmed by PCR amplification that revealed a 712 bp fragment in 55 F1 seedlings of KB × SP951and 88 F1 seedlings of KJ × SP951 (Fig. 1) with mismatch amplification for mutation analysis (MAMA) primer

Summary

Introduction

Late blight, caused by oomycetes pathogen Phytophthora infestans (Mont.) de Bary, is the most devastating potato disease in the world. Major R genes mainly derived from Solanum demissum have been exploited world over including India, to develop late blight resistant cultivars through classical breeding. Classical breeding approach to transfer resistance from this species to cultivated potato is not possible because of differences in ploidy and Endosperm Balance Number [4]. To overcome this problem, the R gene responsible for broad-spectrum resistance in S. bulbocastanum was cloned by two independent groups in USA (RB, [5]) and The Netherlands (Rpi-blb1, [6]).

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