TaTPP‐7A positively feedback regulates grain filling and wheat grain yield through T6P‐SnRK1 signalling pathway and sugar–ABA interaction

Abstract

Summary Grain size and filling are two key determinants of grain thousand‐kernel weight (TKW) and crop yield, therefore they have undergone strong selection since cereal was domesticated. Genetic dissection of the two traits will improve yield potential in crops. A quantitative trait locus significantly associated with wheat grain TKW was detected on chromosome 7AS flanked by a simple sequence repeat marker of Wmc17 in Chinese wheat 262 mini‐core collection by genome‐wide association study. Combined with the bulked segregant RNA‐sequencing (BSR‐seq) analysis of an F2 genetic segregation population with extremely different TKW traits, a candidate trehalose‐6‐phosphate phosphatase gene located at 135.0 Mb (CS V1.0), designated as TaTPP‐7A, was identified. This gene was specifically expressed in developing grains and strongly influenced grain filling and size. Overexpression (OE) of TaTPP‐7A in wheat enhanced grain TKW and wheat yield greatly. Detailed analysis revealed that OE of TaTPP‐7A significantly increased the expression levels of starch synthesis‐ and senescence‐related genes involved in abscisic acid (ABA) and ethylene pathways. Moreover, most of the sucrose metabolism and starch regulation‐related genes were potentially regulated by SnRK1. In addition, TaTPP‐7A is a crucial domestication‐ and breeding‐targeted gene and it feedback regulates sucrose lysis, flux, and utilization in the grain endosperm mainly through the T6P‐SnRK1 pathway and sugar–ABA interaction. Thus, we confirmed the T6P signalling pathway as the central regulatory system for sucrose allocation and source–sink interactions in wheat grains and propose that the trehalose pathway components have great potential to increase yields in cereal crops.

Abscisic Acid Enhances Trehalose Content via OsTPP3 to Improve Salt Tolerance in Rice Seedlings

“…However, it is worth noting that the expression of OsTPP1 and OsTPP3 was reduced in inferior grains of the aba8ox2 mutant, an ABA catabolism gene, resulting in an elevated T6P level and thus promoting grain filling [ 56 ], indicating that an elevated ABA content might not always increase the expression of OsTPP3 in different tissues of rice. In addition, the overexpression of TaTPP - 7A promoted the grain filling of wheat kernels and induced the expression of genes involved in the ABA signaling pathway [ 57 ]. In Arabidopsis , the expression of the ABI4 gene, which encodes a key component of the ABA signaling pathway, is regulated by the AtTPS1 gene [ 58 ].…”

Identification of candidate gene for the defective kernel phenotype using bulked segregant RNA and exome capture sequencing methods in wheat

“…The G-to-A mutation at position 1,049 of the HMGS-7A coding region leads to amino acid change from glycine (Gly) to aspartic acid (Asp). In previous studies, several genes related to grain size and weight have been mapped and cloned on wheat chromosome 7A, including TaTPP-7A (7A, 135.0 Mb; Liu et al., 2023 ), TaGASR7 (7A, 176.0 Mb; Zhang et al., 2015 ), TaTGW-7A (7A, 211.6 Mb; Hu et al., 2016 ), TaGW8 (7A, 257.3 Mb; Yan et al., 2019 ), and TaIAA21 (7A, 488.5 Mb; Jia M et al, 2021 ). The TraesCS7A03G0625900 ( HMGS-7A ) gene identified in this study does not overlap with these reported grain morphology genes.…”

Genome-Wide Identification and Expression Analysis of the Trehalose-6-phosphate Synthase and Trehalose-6-phosphate Phosphatase Gene Families in Rose (Rosa hybrida cv ‘Carola’) under Different Light Conditions

“…For example, overexpression of OsTPP1 in rice promotes seed germination and increases rice yield and stress resistance [ 43 ]. In wheat, TaTPP7 promotes seed grain filling [ 44 ]. However, whether the changes of RhTPS / TPP genes in roses are caused by stress environments or due to different metabolic patterns compared to other plants still needs to be further studied through experiments.…”