Genome-wide identification of GH3 genes in Brassica oleracea and identification of a promoter region for anther-specific expression of a GH3 gene

Background The Gretchen Hagen 3 (GH3) genes encode acyl acid amido synthetases, many of which have been shown to modulate the amount of active plant hormones or their precursors. GH3 genes, especially Group III subgroup 6 GH3 genes, and their expression patterns in economically important B. oleracea var. oleracea have not been systematically identified. Results As a first step to understand regulation and molecular functions of Group III subgroup 6 GH3 genes, 34 GH3 genes including four subgroup 6 genes were identified in B. oleracea var. oleracea. Synteny found around subgroup 6 GH3 genes in B. oleracea var. oleracea and Arabidopsis thaliana indicated that these genes are evolutionarily related. Although expression of four subgroup 6 GH3 genes in B. oleracea var. oleracea is not induced by auxin, gibberellic acid, or jasmonic acid, the genes show different organ-dependent expression patterns. Among subgroup 6 GH3 genes in B. oleracea var. oleracea, only BoGH3.13–1 is expressed in anthers when microspores, polarized microspores, and bicellular pollens are present, similar to two out of four syntenic A. thaliana subgroup 6 GH3 genes. Detailed analyses of promoter activities further showed that BoGH3.13–1 is expressed in tapetal cells and pollens in anther, and also expressed in leaf primordia and floral abscission zones. Conclusions Sixty-two base pairs (bp) region (− 340 ~ − 279 bp upstream from start codon) and about 450 bp region (− 1489 to − 1017 bp) in BoGH3.13–1 promoter are important for expressions in anther and expressions in leaf primordia and floral abscission zones, respectively. The identified anther-specific promoter region can be used to develop male sterile transgenic Brassica plants.

Genome-wide identification of GH3 genes in Brassica oleracea and identification of a promoter region for anther-specific expression of a GH3 gene

Background: The Gretchen Hagen 3 (GH3) genes encode acyl acid amido synthetases, many of which have been shown to modulate the amount of active plant hormones or their precursors. GH3 genes, especially Group Ⅲ subgroup 6 GH3 genes, and their expression patterns in economically important B. oleracea var. oleracea have not been systematically identified. Results: As a first step to understand regulation and molecular functions of Group Ⅲ subgroup 6 GH3 genes, 34 GH3 genes including four subgroup 6 genes were identified in B. oleracea var. oleracea. Synteny found around subgroup 6 GH3 genes in B. oleracea var. oleracea and Arabidopsis thaliana indicated that these genes are evolutionarily related. Although expression of four subgroup 6 GH3 genes in B. oleracea var. oleracea is not induced by auxin, gibberellic acid, or jasmonic acid, the genes show different organ-dependent expression patterns. Among subgroup 6 GH3 genes in B. oleracea var. oleracea, only BoGH3.13-1 is expressed in anthers when microspores, polarized microspores, and bicellular pollens are present, similar to two out of four syntenic A. thaliana subgroup 6 GH3 genes. Detailed analyses of promoter activities further showed that BoGH3.13-1 is expressed in tapetal cells and pollens in anther, and also expressed in leaf primordia and floral abscission zones. Conclusions: Sixty-two base pairs (bp) region (-340 ~ -279 bp upstream from start codon) and about 450 bp region (-1489 to -1017 bp) in BoGH3.13-1 promoter are important for expressions in anther and expressions in leaf primordia and floral abscission zones, respectively. The identified anther-specific promoter region can be used to develop male sterile transgenic Brassica plants.

Genome-wide identification of GH3 genes in Brassica oleracea and identification of a promoter region for anther-specific expression of a GH3 gene

Background: The Gretchen Hagen 3 ( GH3 ) genes encode acyl acid amido synthetases, many of which have been shown to modulate the amount of active plant hormones or their precursors. GH3 genes, especially Group Ⅲ subgroup 6 GH3 genes, and their expression patterns in economically important B. oleracea var. oleracea have not been systematically identified. Results: As a first step to understand regulation and molecular functions of Group Ⅲ subgroup 6 GH3 genes, 34 GH3 genes including four subgroup 6 genes were identified in B. oleracea var. oleracea . Synteny found around subgroup 6 GH3 genes in B. oleracea var. oleracea and Arabidopsis thaliana indicated that these genes are evolutionarily related. Although expression of four subgroup 6 GH3 genes in B. oleracea var. oleracea is not induced by auxin, gibberellic acid, or jasmonic acid, the genes show different organ-dependent expression patterns. Among subgroup 6 GH3 genes in B. oleracea var. oleracea , only BoGH3.13-1 is expressed in anthers when microspores, polarized microspores, and bicellular pollens are present, similar to two out of four syntenic A. thaliana subgroup 6 GH3 genes. Detailed analyses of promoter activities further showed that BoGH3.13-1 is expressed in tapetal cells and pollens in anther, and also expressed in leaf primordia and floral abscission zones. Conclusions: Sixty-two base pairs (bp) region (-340 ~ -279 bp upstream from start codon) and about 450 bp region (-1489 to -1017 bp) in BoGH3.13-1 promoter are important for expressions in anther and expressions in leaf primordia and floral abscission zones, respectively. The identified anther-specific promoter region can be used to develop male sterile transgenic Brassica plants.

Genome-Wide Identification of GH3 Genes in Brassica Oleracea and Identification of a Promoter Region for Anther-Specific Expression of a GH3 Gene

Background:The Gretchen Hagen 3 (GH3) genes encode acyl acid amido synthetases, many of which have been shown to modulate the amount of active plant hormones or their precursors. GH3 genes, especially Group Ⅲ subgroup 6 GH3 genes, and their expression patterns in economically important kale-type Brassica oleracea have not been systematically identified. Results:As a first step to understand regulation and molecular functions of Group Ⅲ subgroup 6 GH3 genes, thirty-four GH3 genes including four subgroup 6 genes were identified In B. oleracea var. oleracea, using TO1000. Synteny found around subgroup 6 GH3 genes in TO1000 and Arabidopsis indicated that these genes are evolutionarily related. Although expression of four subgroup 6 GH3 genes in TO1000 is not induced by auxin, gibberellic acid, and jasmonic acid, the genes show different organ-dependent expression patterns. Only one TO1000 subgroup 6 GH3 gene, Bo2g011210, is expressed in anthers when microspores, polarized microspores, and bicellular pollens are present, similar to two out of four syntenic Arabidopsis subgroup 6 GH3 genes. Detailed analyses of promoter activities of Bo2g011210 further showed that Bo2g011210 is expressed in tapetal cells and pollens in anther, and also expressed in leaf primordia and floral abscission zones. Conclusions:Sixty-two base pair (bp) region (-340 ~ -279 bp upstream from start codon) and about 450 bp region (-1489 to -1017 bp) in Bo2g011210 promoter were found to be important for expressions in anther and expressions in leaf primordia and floral abscission zones, respectively. The identified anther-specific promoter region will be useful to develop male sterile transgenic Brassica plants.

Analysis of cell signaling during floral abscission in arabidopsis

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The shedding of plant organs is known as abscission. Floral abscission in Arabidopsis is regulated by two related receptor[negation symbol]-like protein kinases (RLKs), HAESA and HAESA[negation symbol-like 2 (HAE/HSL2). Double mutants of HAE/HSL2 are completely defective in abscission and retain sepals, petals, and stamen indefinitely. We have utilized genetic suppressor screens of hae hsl2 mutant to identify additional regulatory mechanisms of floral abscission. We have uncovered a series of gain-of-function alleles of the receptor-like protein kinase gene SERK1, as well as loss of function alleles of the gene MAP-KINASE-PHOSPHATASE-1/MKP1. We further show that mutation of two components of the endoplasmic reticulum-associated protein degradation system can suppress a weak hae hsl2 mutant, suggesting that the weak hae hsl2 mutant receptor proteins undergo ER-associated protein degradation. We further perform a number of experiments to examine the impact of phosphorylation on the activity of HAE. These results provide a number of important mechanistic details to our understanding of floral abscission, and suggest many lines of inquiry for future research.

Mechanistic insight into a peptide hormone signaling complex mediating floral organ abscission

Plants constantly renew during their life cycle and thus require to shed senescent and damaged organs. Floral abscission is controlled by the leucine-rich repeat receptor kinase (LRR-RK) HAESA and the peptide hormone IDA. It is unknown how expression of IDA in the abscission zone leads to HAESA activation. Here we show that IDA is sensed directly by the HAESA ectodomain. Crystal structures of HAESA in complex with IDA reveal a hormone binding pocket that accommodates an active dodecamer peptide. A central hydroxyproline residue anchors IDA to the receptor. The HAESA co-receptor SERK1, a positive regulator of the floral abscission pathway, allows for high-affinity sensing of the peptide hormone by binding to an Arg-His-Asn motif in IDA. This sequence pattern is conserved among diverse plant peptides, suggesting that plant peptide hormone receptors may share a common ligand binding mode and activation mechanism.