Fangfang Zhao

Soybean is a dual-purpose crop for food and oil, playing a crucial role in China’s grain production. Seed size and weight are key agronomic traits directly influencing the yield. Cytokinin oxidases/dehydrogenases (CKXs) specifically degrade certain isoforms of endogenous cytokinins (CKs), thereby modulating plant growth and seed development. However, their role in soybeans remains largely uncharacterized. In a previous genome-wide association study of 250 soybean core germplasms, we identified GmCKX3 as a yield-related gene. To elucidate its function, we developed GmCKX3-deficient mutants using CRISPR/Cas9 gene editing in soybean Williams82 and conducted a three-year phenotypic analysis. Loss of GmCKX3 function significantly enhanced the seed size and weight, which was attributed to an increased cell size and fat accumulation in the endosperm. This enhancement was driven by elevated endogenous CK levels resulting from suppressed GmCKX3 expression. Subcellular localization revealed that GmCKX3 resides in the endoplasmic reticulum and predominantly degrades the isopentenyladenine (iP)-type CK. Integrated transcriptomic and metabolomic analyses uncovered key genes and pathways involved in CK regulation, supporting GmCKX3’s central role in seed-trait modulation. These findings advance our understanding of cytokinin-mediated seed development and offer promising targets for molecular breeding aimed at improving the soybean yield.

GATA is a crucial transcription factor involved in plant growth, development, and responses to abiotic stress. Therefore, identifying and exploring GATA transcription factors in maize is of significant importance. In this study, we identified 75 ZmGATA genes based on the pan-genome of maize, which includes 26 high-quality maize genomes. These consist of 58 core genes (present in all 26 lines), 12 non-essential genes (present in 2 to 23 lines), 2 near-core genes (present in 24 to 25 lines), and 3 private genes (present in only 1 line). By evaluating the Ka/Ks ratio of the ZmGATA genes in 26 maize varieties, we found that the Ka/Ks ratios of ZmGATA31, ZmGATA32, ZmGATA36, and ZmGATA9 were greater than 1, which may indicate that these four genes are under positive selection. In contrast, the Ka/Ks ratios of other ZmGATA genes were less than 1, suggesting that these genes may be under purifying selection. In the 26 maize genomes, we observed a significant difference in the expression of ZmGATA8 between varieties affected by structural variations (SVs) and those not affected. In certain varieties, SVs altered conserved structures. Additionally, we analyzed the expression levels of ZmGATA genes in different maize tissues and under abiotic stress. ZmGATA38 and ZmGATA39 were highly expressed in the endosperm, thereby influencing starch synthesis, while ZmGATA7, ZmGATA10, ZmGATA19, ZmGATA28, and ZmGATA40 were found to be associated with abiotic stress responses. These findings provide valuable new resources for functional research on ZmGATA.

Maize, a vital cereal in global agriculture, faces significant yield challenges due to drought exacerbated by climate change. This study explores the genetic and molecular bases of drought resilience in maize, focusing on the EPF/EPFL gene family known for its role in stomatal regulation. Through a genome-wide analysis across seven grass species, we identified and characterized 16 ZmEPF/EPFL genes in maize. Focusing on their gene structure, expression patterns, and evolutionary relationships. The study integrated genome-wide searches, phylogenetic analysis, gene expression profiling under drought and other abiotic stresses, and qRT-PCR validation to elucidate the functional roles of these genes in drought response. Our results demonstrate that specific ZmEPF/EPFL genes are differentially expressed under varying drought conditions, suggesting their involvement in the plant’s adaptive response to water scarcity. Furthermore, interaction analyses reveal that these genes are linked to key processes such as stomatal development and oxidative stress management. This study provides a comprehensive overview of the ZmEPF/EPFL gene family’s contribution to stomatal development and drought tolerance, offering insights that could guide future breeding strategies for drought-resistant maize varieties.