Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0277787 (stigma)
 13,352 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Visual screening of a T-DNA mutagenised population of Arabidopsis thaliana for an absence of silique elongation lead to the isolation of the aborted microspores (ams) mutant that shows a sporophytic recessive male sterile phenotype. Homozygous mutant plants are completely devoid of mature pollen. Pollen degeneration occurs shortly after release of the microspores from the tetrad, prior to pollen mitosis I. Premature tapetum and microspore degeneration are the primary defects caused by this lesion, while a secondary effect is visualised in the stamen filaments, which are reduced in length and lie beneath the receptive stigma at flower opening. The disrupted gene was isolated and revealed a T-DNA element to be inserted into the eighth exon of a basic helix-loop-helix (bHLH) gene located on chromosome II. This protein sequence contains a basic DNA binding domain and two alpha helices separated by a loop, typical of a transcription factor belonging to the MYC sub family of bHLH genes. Therefore, AMS plays a crucial role in tapetal cell development and the post-meiotic transcriptional regulation of microspore development within the developing anther.
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PMID:The Arabidopsis ABORTED MICROSPORES (AMS) gene encodes a MYC class transcription factor. 1253 53

Successful fertilization in plants requires the properly coordinated development of female reproductive tissues, including stigma, style, septum and transmitting tract. We have identified three closely related genes, HECATE1 (HEC1), HECATE2 (HEC2) and HECATE3 (HEC3), the expression domains of which encompass these regions of the Arabidopsis gynoecium. The HEC genes encode putative basic helix-loop-helix (bHLH) transcription factors with overlapping functionality. Depending on the amount of HEC function missing, plants exhibit varying degrees of infertility, defects in septum, transmitting tract and stigma development and impaired pollen tube growth. The observed phenotypes are similar to those reported for mutations in the SPATULA (SPT) gene, which also encodes a bHLH transcription factor required for development of the same female tissues. We show that the HEC proteins can dimerize with SPT in a yeast two-hybrid system, indicating that the HEC genes work in concert with SPT to coordinately regulate development of the female reproductive tract. Furthermore, when the HEC genes are ectopically expressed from the CaMV 35S promoter, some of the resulting transgenic plants show pin-shaped inflorescences, suggesting that the HEC genes are probably involved in auxin-mediated control of gynoecium patterning.
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PMID:The HECATE genes regulate female reproductive tract development in Arabidopsis thaliana. 1785 26