Rice G protein γ subunit <i>qPE9‐1</i> modulates root elongation for phosphorus uptake by involving 14‐3‐3 protein OsGF14b and plasma membrane H <sup>+</sup> ‐ATPase
Ke Wang, Feiyun Xu, Wei Yuan, Dongping Zhang, Jianping Liu, Leyun Sun, Liyou Cui, Jianhua Zhang, Weifeng Xu
Abstract
Summary Heterotrimeric G protein is involved in plant growth and development, while the role of rice ( Oryza sativa ) G protein γ subunit qPE9‐1 in response to low‐phosphorus (LP) conditions remains unclear. The gene expression of qPE9‐1 was significantly induced in rice roots under LP conditions. Rice varieties carrying the qPE9‐1 allele showed a stronger primary root response to LP than the varieties carrying the qpe9‐1 allele (mutant of the qPE9‐1 allele). Transgenic rice plants with the qPE9‐1 allele had longer primary roots and higher P concentrations than those with the qpe9‐1 allele under LP conditions. The plasma membrane (PM) H + ‐ATPase was important for the qPE9‐1 ‐mediated response to LP. Furthermore, OsGF14b, a 14‐3‐3 protein that acts as a key component in activating PM H + ‐ATPase for root elongation, is also involved in the qPE9‐1 mediation. Moreover, the overexpression of OsGF14b in WYJ8 (carrying the qpe9‐1 allele) partially increased primary root length under LP conditions. Experiments using R18 peptide (a 14‐3‐3 protein inhibitor) showed that qPE9‐1 is important for primary root elongation and H + efflux under LP conditions by involving the 14‐3‐3 protein. In addition, rhizosheath weight, total P content, and the rhizosheath soil Olsen‐P concentration of qPE9‐1 lines were higher than those of qpe9‐1 lines under soil drying and LP conditions. These results suggest that the G protein γ subunit qPE9‐1 in rice plants modulates root elongation for phosphorus uptake by involving the 14‐3‐3 protein OsGF14b and PM H + ‐ATPase, which is required for rice P use.