Molecular Identification of Stem Rust Resistance Gene(s) from Pakistani Wheat Cultivars

Wheat is a major part of our diet and 90% of this crop is facing threat of stem rust disease worldwide, which is caused by Puccinia graminis f. spp. tritici (Pgt). In Pakistan, most of the wheat cultivars are susceptible to the disease and very little evidence based data is available about stem rust resistant cultivars. Predictability of Pgt migration from Africa to Pakistan through Iran makes this issue important so that its molecular surveillance is very important to improve our wheat genetically. This study is based on screening of Sr gene family and some other genes (RPG genes) against Pakistani wheat germplasm. Total 108 wheat cultivars were screened for different reported resistant genes. Sr22 gene was selected for further analysis and isolated and cloned. Sr22 was triggered by inducing P. graminis on healthy resistant cultivars such as Mexi-Pak and Auqab 2000. After induction total mRNA was isolated and used to synthesize cDNA for the isolation of full length gene. It was ligated in pUC57 vector and sequenced. The sequence comparison indicated a slight change in nucleotide sequence but amino acid sequences were found to be identical. Screening data and transgenic plants containing Sr22 gene isolated in this study will be shared with wheat breeders to tailor new varieties having better resistance against stem rust. (C) 2019 Friends Science Publishers