Grain weight and grain number are two important traits directly determining grain yield in rice. To date,a lot of genes related to grain weight and grain number have been identified; however, the regulatory mechanism ...Grain weight and grain number are two important traits directly determining grain yield in rice. To date,a lot of genes related to grain weight and grain number have been identified; however, the regulatory mechanism underlying these genes remains largely unknown. In this study, we studied the biological function of OsSPL18 during grain and panicle development in rice. Knockout (KO) mutants of OsSPL18exhibited reduced grain width and thickness, panicle length and grain number, but increased tiller number. Cytological analysis showed that OsSPL18 regulates the development of spikelet hulls by affecting cell proliferation. qRT-PCR and GUS staining analyses showed that OsSPL18 was highly expressed in developing young panicles and young spikelet hulls, in agreement with its function in regulating grain and panicle development. Transcriptional activation experiments indicated that OsSPL18is a functional transcription factor with activation domains in both the N-terminus and C-terminus, and both activation domains are indispensable for its biological functions. Quantitative expression analysis showed that DEP1, a major grain number regulator, was significantly down-regulated in OsSPL18 KO lines.Both yeast one-hybrid and dual-luciferase (LUC) assays showed that OsSPL18 could bind to the DEP1promoter, suggesting that OsSPL18 regulates panicle development by positively regulating the expression of DEP1. Sequence analysis showed that OsSPL18 contains the OsmiR156k complementary sequence in the third exon; 5?RLM-RACE experiments indicated that OsSPL18 could be cleaved by OsmiR156k. Taken together, our results uncovered a new OsmiR156k-OsSPL18-DEP1 pathway regulating grain number in rice.展开更多
Terrestrialization is an important evolutionary process that plants experienced.However,little is known about how land plants acquired aquatic growth behaviors.Here,we integrate multiproxy evidence to elucidate the ev...Terrestrialization is an important evolutionary process that plants experienced.However,little is known about how land plants acquired aquatic growth behaviors.Here,we integrate multiproxy evidence to elucidate the evolution of the aquatic plant duckweed.Three genera of duckweeds show chronologically gradual degeneration in root structure and stomatal function and a decrease in lignocellulose content,accompanied by the contraction of relevant gene families and/or a decline in their transcription levels.The number of genes in main phytohormone pathways is also gradually decreased.The coordinated action of genes involved in auxin signaling and rhizoid development causes a gradual decrease in adventitious roots.Additionally,the significant expansion of the flavonoid pathway is related to the adaptation of duckweeds to floating growth.This study reconstructs the evolutionary history of duckweeds,tracing its journey from land back to water-a reverse trajectory of early land plants.展开更多
基金supported by funds from the Rice Molecular Design Breeding (2016YFD0101801)the National Natural Science Foundation of China (91535102 and 31771760)the Open Research Fund of State Key Laboratory of Hybrid Rice (2016KF09)
文摘Grain weight and grain number are two important traits directly determining grain yield in rice. To date,a lot of genes related to grain weight and grain number have been identified; however, the regulatory mechanism underlying these genes remains largely unknown. In this study, we studied the biological function of OsSPL18 during grain and panicle development in rice. Knockout (KO) mutants of OsSPL18exhibited reduced grain width and thickness, panicle length and grain number, but increased tiller number. Cytological analysis showed that OsSPL18 regulates the development of spikelet hulls by affecting cell proliferation. qRT-PCR and GUS staining analyses showed that OsSPL18 was highly expressed in developing young panicles and young spikelet hulls, in agreement with its function in regulating grain and panicle development. Transcriptional activation experiments indicated that OsSPL18is a functional transcription factor with activation domains in both the N-terminus and C-terminus, and both activation domains are indispensable for its biological functions. Quantitative expression analysis showed that DEP1, a major grain number regulator, was significantly down-regulated in OsSPL18 KO lines.Both yeast one-hybrid and dual-luciferase (LUC) assays showed that OsSPL18 could bind to the DEP1promoter, suggesting that OsSPL18 regulates panicle development by positively regulating the expression of DEP1. Sequence analysis showed that OsSPL18 contains the OsmiR156k complementary sequence in the third exon; 5?RLM-RACE experiments indicated that OsSPL18 could be cleaved by OsmiR156k. Taken together, our results uncovered a new OsmiR156k-OsSPL18-DEP1 pathway regulating grain number in rice.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB1290000 and XDB1290103)the Sichuan Science and Technology Program(Grant No.2024ZDZX0052)+2 种基金the National Aquatic Biological Resource Center(NABRC),Chinathe National Natural Science Foundation of China(Grant No.31770395)the Biological Resources Program,Chinese Academy of Sciences(Grant No.KFJ-BRP-008).
文摘Terrestrialization is an important evolutionary process that plants experienced.However,little is known about how land plants acquired aquatic growth behaviors.Here,we integrate multiproxy evidence to elucidate the evolution of the aquatic plant duckweed.Three genera of duckweeds show chronologically gradual degeneration in root structure and stomatal function and a decrease in lignocellulose content,accompanied by the contraction of relevant gene families and/or a decline in their transcription levels.The number of genes in main phytohormone pathways is also gradually decreased.The coordinated action of genes involved in auxin signaling and rhizoid development causes a gradual decrease in adventitious roots.Additionally,the significant expansion of the flavonoid pathway is related to the adaptation of duckweeds to floating growth.This study reconstructs the evolutionary history of duckweeds,tracing its journey from land back to water-a reverse trajectory of early land plants.
