During the past few decades, great progress has been made in elucidating the molecular genetic control mechanisms of panicle numbers, grain number per panicle and grain weight in rice. Panicle numbers, grain number per panicle, grain weight and seed-setting rate constitute the major determinants of grain yield in rice. Rice ( Oryza sativa L.) is not only the staple food for more than half of the world’s population, but also a model species for plant developmental and genetic studies. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All relevant data are within the paper and its Supporting Information files.įunding: This work was supported by the National Transgenic Science and Technology Program of China (Grants 2016ZX08009-003). Received: FebruAccepted: JPublished: July 14, 2017Ĭopyright: © 2017 Xu et al. PLoS Genet 13(7):Įditor: Ravishankar Palanivelu, University of Arizona, UNITED STATES (2017) OsCNGC13 promotes seed-setting rate by facilitating pollen tube growth in stylar tissues. These findings provide new insights into the molecular genetic control mechanisms of seed-setting rate/grain yield in rice and expand our knowledge on the cyclic nucleotide-gated channel proteins in plant sexual reproduction.Ĭitation: Xu Y, Yang J, Wang Y, Wang J, Yu Y, Long Y, et al. Our results suggest that OsCNGC13 acts as a novel maternal sporophytic factor required for stylar cyt accumulation, extracellular matrix components modification and style cell death, thus facilitating the penetration of pollen tube in the style for successful double fertilization and seed-setting in rice. This work identifies a typical cyclic nucleotide-gated channel protein in rice, OsCNGC13, which can mediate Ca 2+ inward current. However, how the growth of pollen tube is regulated by maternal tissue remains largely elusive. During this long and arduous process, pollen tube requires abundant communication with the surrounding sporophytic maternal tissues. Then, the germinated pollen tubes invade the stigma and navigate through the style transmission tract to reach the micropyle of the embryo sac for fertilization. After pollination, rice pollen grains adhere and hydrate at the surface of stigmatic papilla cells. Rice is not only the staple food for more than half of the world’s population, but also a model species for plant developmental and genetic studies. Based on these results, we propose that OsCNGC13 acts as a novel maternal sporophytic factor required for stylar cyt accumulation, ECM components modification and STT cell death, thus facilitating the penetration of pollen tube in the style for successful double fertilization and seed-setting in rice. Further, the sss1-D mutant has altered extracellular matrix (ECM) components and delayed cell death in the style transmission tract (STT). Consistent with this, accumulation of cytoplasmic calcium concentration ( cyt) is defective in the sss1-D mutant style after pollination. We show that OsCNGC13 is permeable to Ca 2+.
OsCNGC13 is preferentially expressed in the pistils and its expression is dramatically reduced in the heterozygous plant, suggesting a haploinsufficiency nature for the dominant mutant phenotype. Molecular cloning and functional assays reveals that SSS1-D encodes OsCNGC13, a member of the cyclic nucleotide-gated channel family. Cellular examination results show that pollen tube growth is blocked in about half of the mutant styles. In this study, we isolate a dominant low seed-setting rate rice mutant, sss1-D. The molecular mechanisms governing this process remain largely unknown. Rapid and healthy pollen tube growth in the style is required for high seed-setting rate. Seed-setting rate is a critical determinant of grain yield in rice ( Oryza sativa L.).
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