The WUSCHEL-related homeobox gene WOX11 is required to activate shoot-borne crown root development in rice.
In rice (Oryza sativa), the shoot-borne crown roots are the major root type and are initiated at lower stem nodes as part of normal plant development. However, the regulatory mechanism of crown root development is poorly understood. In this work, we show that a WUSCHEL-related Homeobox (WOX) gene, WOX11, is involved in the activation of crown root emergence and growth. WOX11 was found to be expressed in emerging crown roots and later in cell division regions of the root meristem. The expression could be induced by exogenous auxin or cytokinin. Loss-of-function mutation or downregulation of the gene reduced the number and the growth rate of crown roots, whereas overexpression of the gene induced precocious crown root growth and dramatically increased the root biomass by producing crown roots at the upper stem nodes and the base of florets. The expressions of auxin- and cytokinin-responsive genes were affected in WOX11 overexpression and RNA interference transgenic plants. Further analysis showed that WOX11 directly repressed RR2, a type-A cytokinin-responsive regulator gene that was found to be expressed in crown root primordia. The results suggest that WOX11 may be an integrator of auxin and cytokinin signaling that feeds into RR2 to regulate cell proliferation during crown root development.
Zhao
Yu
Y
National Key Laboratory for Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China.
Hu
Yongfeng
Y
Dai
Mingqiu
M
Huang
Limin
L
Zhou
Dao-Xiu
DX
D029681:Arabidopsis Proteins / Q000235:genetics*; D002455:Cell Division / Q000502:physiology; D003583:Cytokinins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D018519:Meristem / Q000502:physiology; D008969:Molecular Sequence Data; D012275:Oryza / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000033:anatomy & histology / Q000254:growth & development; D018520:Plant Shoots / Q000033:anatomy & histology / Q000254:growth & development; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D034622:RNA Interference
D029681:Arabidopsis Proteins; D003583:Cytokinins; D018398:Homeodomain Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; C116421:WUSCHEL protein, Arabidopsis