An autoactive NB-LRR gene causes Rht13 dwarfism in wheat

Borrill P., Mago R., Xu T., Ford B., Williams S.J., Derkx A., Bovill W.D., Hyles J., Bhatt D., Xia X., MacMillan C., White R., Buss W., Molnár I., Walkowiak S., Olsen O.-A., Doležel J., Pozniak C.J., Spielmeyer W.

Keywords: semidwarfing gene, reduced-height (Rht) gene, autoactive NB-LRR, Triticum aestivum L. (wheat)
Abstract: Semidwarfing genes have greatly increased wheat yields globally, yet the widely used gibberellin (GA)-insensitive genes Rht-B1b and Rht-D1b have disadvantages for seedling emergence. Use of the GA-sensitive semidwarfing gene Rht13 avoids this pleiotropic effect. Here, we show that Rht13 encodes a nucleotide-binding site/leucine-rich repeat (NB-LRR) gene. A point mutation in the semidwarf Rht-B13b allele autoactivates the NB-LRR gene and causes a height reduction comparable with Rht-B1b and Rht-D1b in diverse genetic backgrounds. The autoactive Rht-B13b allele leads to transcriptional up-regulation of pathogenesis-related genes including class III peroxidases associated with cell wall remodeling. Rht13 represents a new class of reduced height (Rht) gene, unlike other Rht genes, which encode components of the GA signaling or metabolic pathways. This discovery opens avenues to use autoactive NB-LRR genes as semidwarfing genes in a range of crop species, and to apply Rht13 in wheat breeding programs using a perfect genetic marker.
DOI: 10.1073/pnas.2209875119
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IEB authors: Jaroslav Doležel, Istvan Molnar