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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #351615
Title: Mutations in CsPID encoding a Ser/Thr protein kinase are responsible for round leaf shape in cucumber (Cucumis sativus L.)

Author
item ZHANG, CHAOWEN - Northwest Agriculture And Forestry University
item CHEN, FEIFAN - Northwest Agriculture And Forestry University
item ZHAO, ZIYAO - Northwest Agriculture And Forestry University
item HU, LIANGLIANG - Northwest Agriculture And Forestry University
item LIU, HANQIANG - Northwest Agriculture And Forestry University
item CHENG, ZHIHUI - Northwest Agriculture And Forestry University
item Weng, Yiqun
item CHEN, PENG - Northwest Agriculture And Forestry University
item LI, YUHONG - Northwest Agriculture And Forestry University

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2018
Publication Date: 3/15/2018
Citation: Zhang, C., Chen, F., Zhao, Z., Hu, L., Liu, H., Cheng, Z., Weng, Y., Chen, P., Li, Y. 2018. Mutations in CsPID encoding a Ser/Thr protein kinase are responsible for round leaf shape in cucumber (Cucumis sativus L.). Theoretical and Applied Genetics. 131:1379-1389. https://doi.org/10.1007/s00122-018-3084-8.
DOI: https://doi.org/10.1007/s00122-018-3084-8

Interpretive Summary: Leaf shape is an important plant architecture trait for crop improvement to adapt to different production environments. The formation of leaf shape during plant growth is affected by plant hormones, especially auxin. For example, in the model plant Arabidopsis, the gene PID involved in auxin transportation and distribution affects leaf shape formation, but its role in crop plants is not well studied. Using EMS mutagenesis, we identified two round-leaf (rl) mutants in cucumber. We found both round-leaf mutations were controlled by single recessive genes (rl-1 and rl-2). We took the map-based cloning approach and identified CsPID as the candidate gene of rl-1. The round leaf shape is because of a single nucleotide mutation inside the CsPID gene. The expression of the CsPID gene was significantly reduced in the root, leaf and female flowers of the mutant. We examined the cucumber genome and found there are three copies of PID genes (CsPID, CsPID2 and CSPID2). Among them, only CsPID showed different expression in adult leaves between the wild type and mutant plants. This suggested that CsPID plays a main role in leaf shape formation. We also found the second round leaf mutant had a different mutation in the same gene of CsPID. The two round leaf mutants and the work presented herein provide a good foundation for understanding the molecular mechanisms of CsPID in cucumber leaf development. The mutants may also have potentials in cucumber breeding.

Technical Abstract: Leaf shape is an important plant architecture trait that is affected by plant hormones, especially auxin. In Arabidopsis, PINOID (PID), a regulator for the auxin polar transporter PIN (PIN-FORMED) affects leaf shape formation, but this function of PID in crop plants has not been well studied. From an EMS mutagenesis population, we identified two round-leaf (rl) mutants, C356 and C949. Segregation analysis suggested that both mutations were controlled by single recessive genes, rl-1 and rl-2, respectively. With map-based cloning, we show that CsPID as the candidate gene of rl-1; a non-synonymous SNP in the second exon of CsPID resulted in an amino acid substitution and the round leaf phenotype. As compared in the wild type plant, CsPID had significantly lower expression in the root, leaf and female flowers in C356, which may result in the less developed roots, round leaves and abnormal female flowers, respectively in the rl-1 mutant. Among the three copies of PID genes, CsPID, CsPID2 and CSPID2L (CsPID2-like) in the cucumber genome, CsPID was the only one with significantly differential expression in adult leaves between WT and C356 suggesting CsPID plays a main role in leaf shape formation. The rl-2 mutation in C949 was also cloned, which was due to another SNP in a nearby location of rl-1 in the same CsPID gene. The two round leaf mutants and the work presented herein provide a good foundation for understanding the molecular mechanisms of CsPID in cucumber leaf development.