Genetic mapping and identification of Rht8-B1 that regulates plant height in wheat

Abstract

Background Plant Height (PH) and Spike Compactness (SC) are important agronomic traits that affect yield improvement in wheat crops. The identification of the loci or genes responsible for these traits is thus of great importance for marker-assisted selection in wheat breeding. Results In this study, we used a RIL population with 139 lines derived from crossing between the mutant Rht8-2 and the local wheat variety NongDa5181 (ND5181) to construct a high-density genetic linkage map by applying the Wheat 40K Panel. We identified 7 stable QTLs for PH (3) and SC (4) under two environments using the RIL population, and found that Rht8-B1 is the causal gene of qPH2B.1 by further genetic mapping, gene cloning and gene editing analyses. Our results further showed that two natural variants from GC to TT in the coding region of Rht8-B1 resulted in an amino acid change from G (ND5181) to V (Rht8-2) at the 175th position, reducing PH by 3.6%~6.2% in the RIL population. Moreover, gene editing analysis suggested that the height of T2 generation in Rht8-B1 edited plants was reduced by 5.6%, and that the impact of Rht8-B1 on PH was significantly lower than Rht8-D1. Additionally, distribution analysis of Rht8-B1 in various wheat resources suggested that Rht8-B1b have not been widely utilized in modern wheat breeding Conclusions The combination of Rht8-B1b with other favorable Rht genes might be an alternative approach for developing lodging-resistant crops. Our study brings important information for marker-assisted selection in wheat breeding.