Browsing by Author "Huang, Guoqiang"

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IBR5 regulates leaf serrations development via modulation of the expression of PIN1
(MDPI AG, 2019) Kong, Xiuzhen; Huang, Guoqiang; Xiong, Yali; Zhao, Chunyan; Wang, Jun; Song, Xiaoyun; Giri, Jitender; Zuo, Kaijing
Biodiversity in plant shape is mainly attributable to the diversity of leaf shape, which is largely determined by the transient morphogenetic activity of the leaf margin that creates leaf serrations. However, the precise mechanism underlying the establishment of this morphogenetic capacity remains poorly understood. We report here that INDOLE-3-BUTYRIC ACID RESPONSE 5 (IBR5), a dual-specificity phosphatase, is a key component of leaf-serration regulatory machinery. Loss-of-function mutants of IBR5 exhibited pronounced serrations due to increased cell area. IBR5 was localized in the nucleus of leaf epidermis and petiole cells. Introducing a C129S mutation within the highly conserved VxVHCx2GxSRSx5AYLM motif of IBR5 rendered it unable to rescue the leaf-serration defects of the ibr5-3 mutant. In addition, auxin reporters revealed that the distribution of auxin maxima was expanded ectopically in ibr5-3. Furthermore, we found that the distribution of PIN1 on the plasma membrane of the epidermal and cells around the leaf vein was compromised in ibr5-3. We concluded that IBR5 is essential for the establishment of PIN-FORMED 1 (PIN1)-directed auxin maxima at the tips of leaf serration, which is vital for the elaborated regulation during its formation.
Rice actin binding protein RMD controls crown root angle in response to external phosphate
(Springer Nature, 2018) Huang, Guoqiang; Liang, Wanqi; Sturrock, Craig J.; Pandey, Bipin K.; Giri, Jitender; Mairhofer, Stefan; Wang, Daoyang; Muller, Lukas; Tan, Hexin; York, Larry M.; Yang, Jing; Song, Yu; Kim, Yu-Jin; Qiao, Yang; Xu, Jian; Kepinski, Stefan; Bennett, Malcolm J.; Zhang, Dabing
Root angle has a major impact on acquisition of nutrients like phosphate that accumulate in topsoil and in many species; low phosphate induces shallower root growth as an adaptive response. Identifying genes and mechanisms controlling root angle is therefore of paramount importance to plant breeding. Here we show that the actin-binding protein Rice Morphology Determinant (RMD) controls root growth angle by linking actin filaments and gravity-sensing organelles termed statoliths. RMD is upregulated in response to low external phosphate and mutants lacking of RMD have steeper crown root growth angles that are unresponsive to phosphate levels. RMD protein localizes to the surface of statoliths, and rmd mutants exhibit faster gravitropic response owing to more rapid statoliths movement. We conclude that adaptive changes to root angle in response to external phosphate availability are RMD dependent, providing a potential target for breeders.
Rice auxin influx carrier OsAUX1 facilitates root hair elongation in response to low external phosphate
(Nature Publishing Group, 2018) Giri, Jitender; Bhosale, Rahul; Huang, Guoqiang; Pandey, Bipin K.; Parker, Helen; Zappala, Susan; Yang, Jing; Dievart, Anne; Bureau, Charlotte; Ljung, Karin; Price, Adam; Rose, Terry; Larrieu, Antoine; Mairhofer, Stefan; Sturrock, Craig J.; White, Philip; Dupuy, Lionel; Hawkesford, Malcolm; Perin, Christophe; Liang, Wanqi; Peret, Benjamin; Hodgman, Charlie T.; Lynch, Jonathan; Wissuwa, Matthias; Zhang, Dabing; Pridmore, Tony; Mooney, Sacha J.; Guiderdoni, Emmanuel; Swarup, Ranjan; Bennett, Malcolm J.
Root traits such as root angle and hair length influence resource acquisition particularly for immobile nutrients like phosphorus (P). Here, we attempted to modify root angle in rice by disrupting the OsAUX1 auxin influx transporter gene in an effort to improve rice P acquisition efficiency. We show by X-ray microCT imaging that root angle is altered in the osaux1 mutant, causing preferential foraging in the top soil where P normally accumulates, yet surprisingly, P acquisition efficiency does not improve. Through closer investigation, we reveal that OsAUX1 also promotes root hair elongation in response to P limitation. Reporter studies reveal that auxin response increases in the root hair zone in low P environments. We demonstrate that OsAUX1 functions to mobilize auxin from the root apex to the differentiation zone where this signal promotes hair elongation when roots encounter low external P. We conclude that auxin and OsAUX1 play key roles in promoting root foraging for P in rice.