CRC orthologue from Pisum sativum shows conserved functions in carpel morphogenesis and vascular development

• Published in: Annals of botany Vol. 114; no. 7; pp. 1535 - 1544
• Main Authors: Fourquin, Chloé, Primo, Amparo, Martínez-Fernández, Irene, Huet-Trujillo, Estefanía, Ferrándiz, Cristina
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.11.2014
• Subjects: Amino Acid Sequence; Angiosperms; Arabidopsis - cytology; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - physiology; Carpels; Evolution, Molecular; Flower stigma; Flowering; Flowers - genetics; Flowers - growth & development; Flowers - physiology; Gene expression; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; genes; in situ hybridization; leaves; Legumes; Medicago truncatula; Medicago truncatula - cytology; Medicago truncatula - genetics; Medicago truncatula - growth & development; Medicago truncatula - physiology; Molecular Sequence Data; morphogenesis; Nectaries; Ovaries; peas; Phenotypes; Phylogeny; Pisum sativum; Pisum sativum - cytology; Pisum sativum - genetics; Pisum sativum - growth & development; Pisum sativum - physiology; Plant Leaves - genetics; Plant Leaves - growth & development; Plant Leaves - physiology; Plant organs; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Vascular Bundle - genetics; Plant Vascular Bundle - growth & development; Plant Vascular Bundle - physiology; Poaceae; RNA; Sequence Alignment; Sequence Analysis, DNA; stigma; transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Medicago truncatula; Flower development; floral determinacy; gynoecium, nectary; CRC orthologues; Pisum sativum; YABBY transcription factors; CRABS CLAW; carpel evolution; carpel vasculature
• ISSN: 0305-7364; 1095-8290
• DOI: 10.1093/aob/mcu129

Background and AimsCRABS CLAW (CRC) is a member of the YABBY family of transcription factors involved in carpel morphogenesis, floral determinacy and nectary specification in arabidopsis. CRC orthologues have been functionally characterized across angiosperms, revealing additional roles in leaf vascular development and carpel identity specification in Poaceae. These studies support an ancestral role of CRC orthologues in carpel development, while roles in vascular development and nectary specification appear to be derived. This study aimed to expand research on CRC functional conservation to the legume family in order to better understand the evolutionary history of CRC orthologues in angiosperms.MethodsCRC orthologues from Pisum sativum and Medicago truncatula were identified. RNA in situ hybridization experiments determined the corresponding expression patterns throughout flower development. The phenotypic effects of reduced CRC activity were investigated in P. sativum using virus-induced gene silencing.Key ResultsCRC orthologues from P. sativum and M. truncatula showed similar expression patterns, mainly restricted to carpels and nectaries. However, these expression patterns differed from those of other core eudicots, most importantly in a lack of abaxial expression in the carpel and in atypical expression associated with the medial vein of the ovary. CRC downregulation in pea caused defects in carpel fusion and style/stigma development, both typically associated with CRC function in eudicots, but also affected vascular development in the carpel.ConclusionsThe data support the conserved roles of CRC orthologues in carpel fusion, style/stigma development and nectary development. In addition, an intriguing new aspect of CRC function in legumes was the unexpected role in vascular development, which could be shared by other species from widely diverged clades within the angiosperms, suggesting that this role could be ancestral rather than derived, as so far generally accepted.