Lectin receptor-like kinase LecRK-VIII.2 is a missing link in MAPK signaling-mediated yield control.

The energy allocation for vegetative and reproductive growth is regulated by developmental signals and environmental cues, which subsequently affects seed output. However, the molecular mechanism underlying how plants coordinate yield-related traits to control yield in changing source-sink relationships remains largely unknown. Here, we discovered the lectin receptor-like kinase LecRK-VIII.2 as a specific receptor-like kinase that coordinates silique number, seed size, and seed number to determine seed yield in Arabidopsis (Arabidopsis thaliana). The lecrk-VIII.2 mutants develop smaller seeds, but more siliques and seeds, leading to increased yield. In contrast, the plants overexpressing LecRK-VIII.2 form bigger seeds, but less siliques and seeds, which results in similar yield to that of wild-type plants. Interestingly, LecRK-VIII.2 promotes the growth of the rosette, root, and stem by coordinating the source-sink relationship. Additionally, LecRK-VIII.2 positively regulates cell expansion and proliferation in the seed coat, and maternally controls seed size. The genetic and biochemical analyses demonstrated that LecRK-VIII.2 acts upstream of the mitogen-activated protein kinase (MAPK) gene MPK6 to regulate silique number, seed size, and seed number. Collectively, these findings uncover LecRK-VIII.2 as an upstream component of the MAPK signaling pathway to control yield-related traits and suggest its potential for crop improvement aimed at developing plants with stable yield, a robust root system, and improved lodging resistance.

Comprehensive genomic survey, structural classification and expression analysis of C2H2-type zinc finger factor in wheat (Triticum aestivum L.).

BACKGROUND: The C2H2-type zinc finger proteins (C2H2-ZFPs) are one of major classes of transcription factors that play important roles in plant growth, development and stress responses. Limit information about the C2H2-ZF genes hinders the molecular breeding in bread wheat (Triticum aestivum). RESULTS: In this study, 457 C2H2-ZFP proteins (including 253 splice variants), which contain four types of conserved domain (named Q, M, Z, and D), could be further classified into ten subsets. They were identified to be distributed in 21 chromosomes in T. aestivum. Subset-specific motifs, like NPL-, SFP1-, DL- (EAR-like-motif), R-, PL-, L- and EK-, might make C2H2-ZFP diverse multifunction. Interestingly, NPL- and SFP1-box were firstly found to be located in C2H2-ZFP proteins. Synteny analyses showed that only 4 pairs of C2H2 family genes in T. aestivum, 65 genes in B. distachyon, 66 genes in A. tauschii, 68 genes in rice, 9 genes in Arabidopsis, were syntenic relationships respectively. It indicated that TaZFPs were closely related to genes in Poaceae. From the published transcriptome data, totally 198 of 204 TaC2H2-ZF genes have expression data. Among them, 25 TaC2H2-ZF genes were certificated to be significantly differentially expressed in 5 different organs and 15 different development stages by quantitative RT-PCR. The 18 TaC2H2-ZF genes were verified in response to heat, drought, and heat & drought stresses. According to expression pattern analysis, several TaZFPs, like Traes_5BL_D53A846BE.1, were not only highly expressed in L2DAAs, RTLS, RMS, but also endowed tolerance to drought and heat stresses, making them good candidates for molecular breeding. CONCLUSIONS: This study systematically characterized the TaC2H2-ZFPs and their potential roles in T. aestivum. Our findings provide new insights into the C2H2-ZF genes in T. aestivum as well as a foundation for further studies on the roles of TaC2H2-ZF genes in T. aestivum molecular breeding.