An analysis of the functionality of molecular markers related to the Lr19 gene conditioning resistance to wheat leaf rust

Abstract

Among all cereals, common wheat (Triticum aestivum L.) occupies the largest area of crops worldwide. Wheat leaf rust, caused by the pathogen Puccinia recondita f. sp. tritici considerably reduces the yield of wheat. Breeding for resistance combined with selection based on molecular markers may become an effective tool in the struggle against fungal diseases. Lr19 is the gene that carries high resistance to wheat leaf rust. In recent years, we have seen the development of many molecular markers in close neighbourhood of the Lr19 gene, e.g., SCS265, SCS253, GB, Xwmc221, XustSSR2001-7DL, Xgwm37 and Xgwm44. The aim of the study was to investigate the functionality of molecular markers related to the Lr19 gene. The study was based on two reference genotypes with the Lr19 gene ('Agatha' and Lr19) and three lines strongly infested by wheat leaf rust. Seven molecular markers were analysed, but only two of them (GB and Xwmc221) proved to be specific to the gene under study. These markers were used for analysis of 25 wheat genotypes, which were evaluated for leaf rust resistance in field conditions to confirm their usefulness for selection of breeding material. These findings point to the need of continuous search for functional molecular markers giving repeatable and reliable results.

The Efficacity Investigation for Some Markers Detecting Yellow Rust Resistance Genes in Bread Wheat Varieties

“…More than seventy resistance genes have been characterized using molecular studies [28]. It has been reported that DNA amplification fragments obtained using PCR markers identifying these genes may be a specific indicator of disease resistance [29,30,31,32,33]. Determination of resistance gene regions in wheat contributed greatly to the development of markers and the rapid identification of resistant varieties using molecular methods.…”

The Most Important Fungal Diseases of Cereals—Problems and Possible Solutions

“…As shown by Anwar et al [78], there is a large variation in resistance to brown rust in common wheat, so that resistant lines can be isolated and used for further resistance breeding. In particular, the Lr19 gene, which has a significant effect on resistance in wheat, should be considered, with GB and Xwmc221 as good markers [79]. Fungicide protection in rust prevention can include synthetic fungicide applications as well as plant extracts.…”

Transcriptome analysis of Lr19-virulent mutants provides clues for the AvrLr19 of Puccinia triticina

“…It has great potential in wheat breeding program in China. Although Lr19 has not been cloned, yet many molecular markers closely linked to the Lr19 gene have been developed, such as SCS265 , SCS253 , GB , Xwmc221 , XustSSR2001-7DL , Xgwm37 and Xgwm44 , and two of them ( GB and Xwmc221 ) proved to be specific to Lr19 ( Kiel et al, 2020 ). To prevent Lr19 from being out-competed by newly emergent virulent races and enable the long-term deployment of Lr19 in leaf rust-resistant wheat varieties, it is key to clone avirulent gene AvrLr19 that can be recognized by wheat leaf rust resistance gene Lr19 , determine the molecular mechanism of AvrLr19 and Lr19 interactions, and monitor the natural Pt population changes in response to Lr19 resistance.…”