Genome-wide survey of KT/HAK/KUP genes in the genus Citrullus and analysis of their involvement in K + -deficiency and drought stress responses in between C. lanatus and C. amarus

• Published in: BMC genomics Vol. 25; no. 1; pp. 836 - 15
• Main Authors: Cheng, Rui, Zhao, Zhengxiang, Tang, Yan, Gu, Yan, Chen, Guodong, Sun, Yudong, Wang, Xuezheng
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 05.09.2024; BioMed Central; BMC
• Subjects: Abiotic stress; Agronomy; Analysis; Cation Transport Proteins - genetics; Cation Transport Proteins - metabolism; Chromosomes; Citrullus; Citrullus - genetics; Citrullus - growth & development; Citrullus - metabolism; Complementation; Demand analysis; Diseases and pests; Domestication; Drought; Droughts; Environmental aspects; Environmental stress; Enzymatic activity; Enzyme activity; Enzymes; Force distribution; Fruits; Functionals; Gene expression; Gene Expression Regulation, Plant; Genes; Genetic aspects; Genome, Plant; Genomes; Genomic analysis; Genomics; Genotype & phenotype; Germplasm; Growth; Homeostasis; Horticultural crops; K+ transport; Leaves; Multigene Family; Pangenome gene family; Phylogenetics; Phylogeny; Physiology; Plant growth; Plant heat tolerance; Plant hormones; Plant Proteins - genetics; Plant Proteins - metabolism; Potassium - metabolism; Potassium Deficiency - genetics; Potassium Deficiency - metabolism; Promoter Regions, Genetic; Regulatory sequences; Seedlings; Seeds; Signal transduction; Starvation; Stress, Physiological - genetics; Surveys; Water melons; Watermelon; Watermelons; Yeasts; China; Gene expression; Watermelon; K+ transport; Pangenome gene family
• ISSN: 1471-2164; 1471-2164
• DOI: 10.1186/s12864-024-10712-5

The KT/HAK/KUP is the largest K transporter family in plants, playing crucial roles in K absorption, transport, and defense against environmental stress. Sweet watermelon is an economically significant horticultural crop belonging to the genus Citrullus, with a high demand for K during its growth process. However, a comprehensive analysis of the KT/HAK/KUP gene family in watermelon has not been reported. 14 KT/HAK/KUP genes were identified in the genomes of each of seven Citrullus species. These KT/HAK/KUPs in watermelon were unevenly distributed across seven chromosomes. Segmental duplication is the primary driving force behind the expansion of the KT/HAK/KUP family, subjected to purifying selection during domestication (Ka/Ks < 1), and all KT/HAK/KUPs exhibit conserved motifs and could be phylogenetically classified into four groups. The promoters of KT/HAK/KUPs contain numerous cis-regulatory elements related to plant growth and development, phytohormone response, and stress response. Under K deficiency, the growth of watermelon seedlings was significantly inhibited, with cultivated watermelon experiencing greater impacts (canopy width, redox enzyme activity) compared to the wild type. All KT/HAK/KUPs in C. lanatus and C. amarus exhibit specific expression responses to K -deficiency and drought stress by qRT-PCR. Notably, ClG42_07g0120700/CaPI482276_07g014010 were predominantly expressed in roots and were further induced by K -deficiency and drought stress. Additionally, the K transport capacity of ClG42_07g0120700 under low K stress was confirmed by yeast functional complementation assay. KT/HAK/KUP genes in watermelon were systematically identified and analyzed at the pangenome level and provide a foundation for understanding the classification and functions of the KT/HAK/KUPs in watermelon plants.