The HD-Zip IV gene GaHOX1 from cotton is a functional homologue of the Arabidopsis GLABRA2.
Most of the plant homeodomain-containing proteins play important roles in organ patterning and development, and Arabidopsis GLABRA2 (GL2), a member of the class IV homeodomain-leucine zipper (HD-ZIP) proteins, is a trichome and non-root hair cell regulator. Here we report the analysis of two cotton homeodomain-containing proteins, GaHOX1 and GaHOX2, isolated from the diploid cotton Gossypium arboreum. Both GaHOX1 and GaHOX2 belong to the class IV HD-ZIP family. When expressed under the control of the GL2 promoter, GaHOX1 rescued trichome development of an Arabidopsis glabrous mutant of gl2-2 (SALK_130213), whereas GaHOX2 did not. On the other hand, expression of GaHOX1 with a Cauliflower mosaic virus (CaMV) 35S promoter in the wild-type Arabidopsis plants suppressed the trichome development just as the GL2 ectopic expression. Expression analysis by Northern, RT-PCR and in situ hybridization indicated that GaHOX1 is predominantly expressed in cotton fiber cells at early developmental stages, consistent with its putative role in regulating cotton fiber development, while GaHOX2 is expressed in both fiber and other ovular tissues, including outer and inner integuments. Our results suggest that GaHOX1 is a functional homolog of GL2 in plant trichome development.
Guan
Xue-Ying
XY
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
Li
Qian-Jin
QJ
Shan
Chun-Min
CM
Wang
Shui
S
Mao
Ying-Bo
YB
Wang
Ling-Jian
LJ
Chen
Xiao-Ya
XY
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000235:genetics / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; C089991:GL2 protein, Arabidopsis; D018398:Homeodomain Proteins; D010940:Plant Proteins