Arabidopsis plants adapt to warm temperatures by promoting hypocotyl growth primarily through the basic helix-loop-helix transcription factor PIF4 and its downstream genes involved in auxin responses,which enhance cel...Arabidopsis plants adapt to warm temperatures by promoting hypocotyl growth primarily through the basic helix-loop-helix transcription factor PIF4 and its downstream genes involved in auxin responses,which enhance cell division.In the current study,we discovered that cell wall-related calcium-binding protein 2(CCaP2)and its paralogs CCaP1 and CCaP3 function as positive regulators of thermo-responsive hypocotyl growth by promoting cell elongation in Arabidopsis.Interestingly,mutations in CCaP1/CCaP2/CCaP3 do not affect the expression of PIF4-regulated classic downstream genes.However,they do noticeably reduce the expression of xyloglucan endotransglucosylase/hydrolase genes,which are involved in cell wall modification.We also found that CCaP1/CCaP2/CCaP3 are predominantly localized to the plasma membrane,where they interact with the plasma membrane H^(+)-ATPases AHA1/AHA2.Furthermore,we observed that vanadate-sensitive H^(+)-ATPase activity and cell wall pectin and hemicellulose contents are significantly increased in wild-type plants grown at warm temperatures compared with those grown at normal growth temperatures,but these changes are not evident in the ccap1-1 ccap2-1 ccap3-1 triple mutant.Overall,our findings demonstrate that CCaP1/CCaP2/CCaP3 play an important role in controlling thermo-responsive hypocotyl growth and provide new insights into the alternative pathway regulating hypocotyl growth at warm temperatures through cell wall modification mediated by CCaP1/CCaP2/CCaP3.展开更多
基金supported by a grant from the National Natural Science Foundation of China(31872653).
文摘Arabidopsis plants adapt to warm temperatures by promoting hypocotyl growth primarily through the basic helix-loop-helix transcription factor PIF4 and its downstream genes involved in auxin responses,which enhance cell division.In the current study,we discovered that cell wall-related calcium-binding protein 2(CCaP2)and its paralogs CCaP1 and CCaP3 function as positive regulators of thermo-responsive hypocotyl growth by promoting cell elongation in Arabidopsis.Interestingly,mutations in CCaP1/CCaP2/CCaP3 do not affect the expression of PIF4-regulated classic downstream genes.However,they do noticeably reduce the expression of xyloglucan endotransglucosylase/hydrolase genes,which are involved in cell wall modification.We also found that CCaP1/CCaP2/CCaP3 are predominantly localized to the plasma membrane,where they interact with the plasma membrane H^(+)-ATPases AHA1/AHA2.Furthermore,we observed that vanadate-sensitive H^(+)-ATPase activity and cell wall pectin and hemicellulose contents are significantly increased in wild-type plants grown at warm temperatures compared with those grown at normal growth temperatures,but these changes are not evident in the ccap1-1 ccap2-1 ccap3-1 triple mutant.Overall,our findings demonstrate that CCaP1/CCaP2/CCaP3 play an important role in controlling thermo-responsive hypocotyl growth and provide new insights into the alternative pathway regulating hypocotyl growth at warm temperatures through cell wall modification mediated by CCaP1/CCaP2/CCaP3.
