Dataset Information

Specificity determinants and diversification of the Brassica self-incompatibility pollen ligand.

ABSTRACT: Self-incompatibility in crucifers is effected by allele-specific interactions between the highly polymorphic stigmatic S locus receptor kinase (SRK) and its pollen ligand, the S locus cysteine-rich protein (SCR). Here we show that specificity in SCR function is determined by four contiguous amino acids in one variant, indicating that the minimum sequence requirement for gaining a new specificity can be low. We also provide evidence for an extraordinarily high degree of evolutionary flexibility in SCR, whereby SCR can tolerate extensive amino acid changes within the limits of maintaining the same predicted overall structure. This remarkable adaptability suggests a hypothesis for generation of new self-incompatibility specificities by gradual modification of SRK-SCR affinities and, more generally, for functional specialization within families of homologous ligands and receptors.

SUBMITTER: Chookajorn T

PROVIDER: S-EPMC327116 | biostudies-literature | 2004 Jan

REPOSITORIES: biostudies-literature

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Specificity determinants and diversification of the Brassica self-incompatibility pollen ligand.

Chookajorn Thanat T Kachroo Aardra A Ripoll Daniel R DR Clark Andrew G AG Nasrallah June B JB

Proceedings of the National Academy of Sciences of the United States of America 20031223 4

Self-incompatibility in crucifers is effected by allele-specific interactions between the highly polymorphic stigmatic S locus receptor kinase (SRK) and its pollen ligand, the S locus cysteine-rich protein (SCR). Here we show that specificity in SCR function is determined by four contiguous amino acids in one variant, indicating that the minimum sequence requirement for gaining a new specificity can be low. We also provide evidence for an extraordinarily high degree of evolutionary flexibility i ...[more]

PMID: 14694189

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Project description:In angiosperms, self-incompatibility (SI) is a common and widespread mechanism for plant prevention of inbreeding, and late-acting self-incompatibility (LSI) may be ancestral in the group. In this work, we studied Schima superba, a species in Theaceae that is a commercially important timer and fire-resistant tree, and revealed its LSI mechanism. Hormones, enzymes, transcriptomes, and proteins were compared between self-pollination (SP) and outcross pollination (OP) in the styles and ovaries from 0 to 120 h after pollination. The self-pollen tubes grew to the bottom of the style and entered the ovary within 48 h but failed to penetrate the ovule. Meanwhile, the hormone and peroxidase levels dramatically changed. Transcriptome and proteome analyses explored the molecular mechanisms of LSI and candidate genes related to LSI in S. superba. Overall, 586.71 million reads were obtained, and 79,642 (39.08%) unigenes were annotated. KEGG and GO analysis showed that there were 4531 differentially expressed genes (DEGs) and 82 differentially expressed proteins (DEPs) at 48 h in self- (SP) versus outcross pollination (OP). Among these, 160 DEGs and 33 DEPs were involved in pollen-pistil interactions. "Pollen-pistil interaction," "signal recognition," and "component of membrane" were downregulated in SP, whereas "cell wall and membrane biosynthetic process," and "oxidoreductase activity" were upregulated. The DEGs involved with S-RNases and SCF during SP suggested that the LSI occurred at 48 h in the ovary and that the LSI in S. superba was under gametophyte control. Calcium ion increase and release, mitochondrial function loss, and ROS disruption further aggravated PCD progress and cell death. The LSI of S. superba, which happened 48 h after pollination, was a key time point. The incompatibility PT ceased growth in the ovary because of S-RNase recognition and PCD in this organ. This study highlights the LSI molecular mechanism in S. superba and provides a reference to other species in Theaceae.

Dataset Information

Specificity determinants and diversification of the Brassica self-incompatibility pollen ligand.

Publications

Specificity determinants and diversification of the Brassica self-incompatibility pollen ligand.

Similar Datasets

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