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The WUSCHEL ‐ RELATED HOMEOBOX 3 gene Pa WOX 3 regulates lateral organ formation in Norway spruce
Author(s) -
Alvarez José M.,
Sohlberg Joel,
Engström Peter,
Zhu Tianqing,
Englund Marie,
Moschou Panagiotis N.,
Arnold Sara
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13536
Subject(s) - homeobox , meristem , embryo , biology , cotyledon , microbiology and biotechnology , gene expression , elongation , downregulation and upregulation , botany , gene , shoot , biochemistry , materials science , ultimate tensile strength , metallurgy
Summary In angiosperms, WUSCHEL ‐ RELATED HOMEOBOX 3 ( WOX 3 ) genes are required for the recruitment of founder cells from the lateral domains of shoot meristems that form lateral regions of leaves. However, the regulation of the formation of lateral organs in gymnosperms remains unknown. By using somatic embryos of Norway spruce ( Picea abies ) we have studied the expression and function of Pa WOX 3 during embryo development. The mRNA abundance of Pa WOX 3 was determined by quantitative real‐time PCR , and the spatial expression of Pa WOX 3 was analysed by histochemical β ‐ glucuronidase ( GUS ) assays and in situ mRNA hybridization. To investigate the function of Pa WOX 3 , we analysed how downregulation of Pa WOX 3 in RNA interference lines affected embryo development and morphology. Pa WOX 3 was highly expressed in mature embryos at the base of each cotyledon close to the junction between the cotyledons, and in the lateral margins of cotyledons and needles, separating them into an adaxial and an abaxial side. Downregulation of the expression of Pa WOX 3 caused defects in lateral margin outgrowth in cotyledons and needles, and reduced root elongation. Our data suggest that the WOX 3 function in margin outgrowth in lateral organs is conserved among the seed plants, whereas its function in root elongation may be unique to gymnosperms.