New semi‐dwarfing alleles with increased coleoptile length by gene editing of gibberellin 3‐oxidase 1 using CRISPR‐Cas9 in barley (Hordeum vulgare L.)

Abstract

Summary The green revolution was based on genetic modification of the gibberellin (GA) hormone system with “dwarfing” gene mutations that reduces GA signals, conferring shorter stature, thus enabling plant adaptation to modern farming conditions. Strong GA‐related mutants with shorter stature often have reduced coleoptile length, discounting yield gain due to their unsatisfactory seedling emergence under drought conditions. Here we present gibberellin (GA) 3‐oxidase1 (GA3ox1) as an alternative semi‐dwarfing gene in barley that combines an optimal reduction in plant height without restricting coleoptile and seedling growth. Using large‐scale field trials with an extensive collection of barley accessions, we showed that a natural GA3ox1 haplotype moderately reduced plant height by 5–10 cm. We used CRISPR/Cas9 technology, generated several novel GA3ox1 mutants and validated the function of GA3ox1. We showed that altered GA3ox1 activities changed the level of active GA isoforms and consequently increased coleoptile length by an average of 8.2 mm, which could provide essential adaptation to maintain yield under climate change. We revealed that CRISPR/Cas9‐induced GA3ox1 mutations increased seed dormancy to an ideal level that could benefit the malting industry. We conclude that selecting HvGA3ox1 alleles offers a new opportunity for developing barley varieties with optimal stature, longer coleoptile and additional agronomic traits.

Investigating the genetic control of plant development under speed breeding conditions

“…Both PPD-H1 and ELF3 are linked to the expression of FT1 and GA20ox genes that are downstream floral integrators that control the flowering response (Boden et al, 2014; Campoli et al, 2012; Cheng et al, 2023; Faure et al, 2012; Turner et al, 2005). ELF3 delays the flowering response whereas PPD-H1 accelerates the response in long days.…”

Grain yield improvement by genome editing of TaARF12 that decoupled peduncle and rachis development trajectories via differential regulation of gibberellin signalling in wheat

“…Among them, GA is the most important hormone for plant height regulation. In addition to the rice sd1 and the wheat Rht1 and Rht2 that are involved in GA signalling, GA biogenesis and metabolizing genes, such as the barley gibberellin 3‐oxidase 1 (Cheng et al ., 2023), the wheat Rht12 (Sun et al ., 2019), Rht18 (Ford et al ., 2018) and Rht24b (Tian et al ., 2022), have also been identified to participate in plant height development. Auxin signalling genes, such as auxin response factors (ARFs), played important roles in this process too.…”