A genotypic difference in primary root length is associated with the inhibitory role of transforming growth factor‐beta receptor‐interacting protein‐1 on root meristem size in wheat

Abstract

SUMMARYPreviously we identified a major quantitative trait locus (QTL) qTaLRO-B1 for primary root length (PRL) in wheat. Here we compare proteomics in the roots of the qTaLRO-B1 QTL isolines 178A, with short PRL and small meristem size, and 178B, with long PRL and large meristem size. A total of 16 differentially expressed proteins were identified: one, transforming growth factor (TGF)-beta receptor-interacting protein-1 (TaTRIP1), was enriched in 178A, while various peroxidases (PODs) were more abundantly expressed in 178B. The 178A roots showed higher TaTRIP1 expression and lower levels of the unphosphorylated form of the brassinosteroid (BR) signaling component BZR1, lower expression of POD genes and reduced POD activity and accumulation of the superoxide anion O 2 À in the root elongation zone compared with the 178B roots. Low levels of 24-epibrassinolide increased POD gene expression and root meristem size, and rescued the short PRL phenotype of 178A. TaTRIP1 directly interacted with the BR receptor TaBRI1 of wheat. Moreover, overexpressing TaTRIP1 in Arabidopsis reduced the abundance of unphosphorylated BZR1 protein, altered the expression of BR-responsive genes, inhibited POD activity and accumulation of the O 2 − in the root tip and inhibited root meristem size. Our data suggested that TaTRIP1 is involved in BR signaling and inhibited root meristem size, possibly by reducing POD activity and accumulation of O 2 − in the root tip. We further demonstrated a negative correlation between the level of TaTRIP1 mRNA and PRL of landraces and modern wheat varieties, providing a valuable insight for better understanding of the molecular mechanism underlying the genotypic differences in root morphology of wheat in the future.

Comparative Proteomic Analysis Provides New Insights Into Low Nitrogen-Promoted Primary Root Growth in Hexaploid Wheat

“…The glutathione-ascorbate cycle is known as a hydrogen peroxide reducing system (Noctor and Foyer, 1998), in which glutathione acts as a redox buffer against reactive oxygen species (ROS), helping to maintain a reducing environment in vivo . This is supported by the finding that differences in accumulation of ROS in the root tip significantly affect root growth (Dunand et al, 2007; Tsukagoshi et al, 2010; He et al, 2014).…”

Identification and characterization of CircRNAs involved in the regulation of wheat root length

“…Previous studies have shown that plant root growth and development are controlled by phytohormones and sustained by the root apical meristem (RAM) [6–12]. Besides, redox regulation and the balance of ROS also have important roles in maintaining RAM activity [13–15]. Therefore, the growth and development of plant roots are regulated by complex hormone signals and other related pathways.…”

QTLs for seedling traits under salinity stress in hexaploid wheat

“…However, we did not detect any QTLs for root traits in this chromosomal region under ST condition, indicated that the expression of this locus is inhibited and very sensitive to salt stress. Actually this QTL has been proved to be involved in brassinosteroids (BRs) signaling pathway (HE et al, 2014) and BRs is also known to confer salt stress tolerance (KRISHNA et al, 2003;ZHU et al, 2016). The qTDWR-3A located on chromosome 3A between SSR marker Xgwm156.2 and Xbarc324, and explained 15.0% TDWR phenotypic variation.…”