Meta-QTLs for multiple disease resistance involving three rusts in common wheat (Triticum aestivum L.)

Abstract

Rust diseases in wheat are a major threat to global food security, therefore, the development of multiple disease-resistant cultivars (resistant to all three rusts) is a major goal in all wheat breeding programs worldwide. In the present study, meta-QTLs and candidate genes for multiple disease resistance (MDR) involving all the three rusts were identified using 152 individual QTL mapping studies for resistance to leaf rust (LR), stem rust (SR), and yellow rust (YR). From these 152 studies, a total of 1,146 QTLs for resistance to the three rusts were retrieved, which included 368 QTLs for LR, 291 QTLs for SR, and 487 QTLs for YR. Of these 1,146 QTLs, only 718 QTLs could be projected onto the consensus map saturated with 234,619 markers. Meta-analysis of the projected QTLs resulted in the identification of 86 MQTLs, which included 71 MDR-MQTLs. Ten of these MDR-MQTLs were referred to as the ‘Breeders’ MQTLs’. Seventy-eight of the 86 MQTLs could also be anchored to the physical map of the wheat genome and 54 MQTLs were validated by marker-trait associations identified during earlier genome-wide association studies. Twenty MQTLs (including 17 MDR-MQTLs) identified in the present study were co-localized with 42 known R genes. In silico expression analysis allowed identification of several differentially expressed candidate genes encoding proteins carrying different domains including the following: NBS-LRR, WRKY domains, F-box domains, sugar transporters, transferases, etc. The introgression of these MDR loci into high-yielding cultivars should prove useful for developing high yielding cultivars with resistance to all three rusts.

Consensus genomic regions associated with grain protein content in hexaploid and tetraploid wheat

“…From the 459 QTLs retrieved from 48 mapping studies, 304 QTLs could be projected onto the consensus genetic map. Due to some of the obvious reasons mentioned previously, the remaining 155 QTLs were unable to be projected onto the consensus map ( Pal et al, 2022 ; Gudi et al, 2022 ). After QTL projection, a meta-analysis was performed which resulted in the identification of 65 potential genomic regions [including 57 MQTLs (each involving at least 2 QTLs derived from different studies) and 7 QTL hotspots (each involving multiple QTLs derived from a single study)] associated with GPC ( Figures 3 , 4A ) based on 233 initial QTLs leaving 45 initial QTLs as singletons (single QTLs) and 26 QTLs with peaks outside the supporting intervals of identified potential genomic regions.…”

“…Out of the 57 predicted MQTLs and 7 QTL hotspots, 19 MQTLs and 2 QTL hotspots overlapped with MTAs identified for GPC in recent GWA studies in wheat. In some of the earlier studies of meta-analysis, MQTLs for other traits of economic importance have also been validated using this method (Aduragbemi and Soriano, 2021; Gudi et al, 2022 ; Saini et al, 2021 ; Pal et al, 2022 ; Yang et al, 2021 ). In these earlier studies, only 38.66, 47.22, 78.57, 58.33, 69.23, and 61.37% of the physically anchored MQTLs were confirmed using GWAS data.…”

“…The hexaploid bread wheat ( Triticum aestivum L.) is the major food crop for approximately one-third of the world population with 760.93 million thousand tonnes of production from a growing area of over 219 million thousand hectares ( https://www.fao.org ). It constitutes the 20 percent dietary component of both calories and protein in the human diet ( Peng et al, 2011 ; Pal et al, 2022 ). The tetraploid durum wheat ( Triticum turgidum L. subsp.…”

“…Significant genomic regions are associated with several economically important traits such as grain yield and its attributing parameters ( Saini et al, 2022c ), nitrogen physiology ( Sandhu N. et al, 2021b ; Saini et al, 2021 ), tolerance to environmental stresses ( Kumar et al, 2021 ; Pal et al, 2021 ), single disease resistance such as leaf rust and multiple disease resistance ( Amo and Soriano, 2022 . ; Pal et al, 2022 ; Saini et al, 2022a ) in wheat and other cereal crops. The MQTLs related to nutritional and quality traits have been reported in durum and bread wheat ( Quraishi et al, 2017 ; Soriano et al, 2021 ; Gudi et al, 2022 ).…”