Cloning and haplotype analysis of TaSTE, which is associated with plant height in bread wheat (Triticum aestivum L.)

Sterol methyltransferase 1 (STE1) catalyzes ∆7 sterol C-5 desaturation in the conversion of 24-methylenecholesterol to campestral in brassinosteroid (BR) biosynthesis, and STE1 has been proven to influence plant architecture by controlling the BR levels in Arabidopsis. In the present study, TaSTE (wheat), the ortholog of AtSTE1 (Arabidopsis), was cloned and mapped to wheat chromosome homologous group 3 in the interval between simple sequence repeats (SSRs) markers CWM48.1 and WMC532, with genetic distances of 17.7 and 7.6 cM, respectively. Both linkage and association analyses revealed that TaSTE-A1 was significantly associated with plant height in bread wheat. In silico expression results showed similar expression patterns among TaSTE, HvSTE1 (barley), OsSTE1 (also known as OsDWF7 in rice), and AtSTE1, suggesting that these orthologs might share common functions among wheat, barley, rice, and Arabidopsis. The haplotype frequencies in wild species, landraces, and modern cultivars indicated that haplotype II (Hap II) was associated with reduced plant height and positively selected during modern breeding improvement. One pair of complementary allele-specific polymerase chain reaction (PCR) markers can distinguish haplotype I (Hap I) and Hap II and could be developed to assist selection in wheat architecture breeding.