The role of Arabidopsis ABCG9 and ABCG31 ATP binding cassette transporters in pollen fitness and the deposition of steryl glycosides on the pollen coat.
Plant Cell
; 26(1): 310-24, 2014 Jan.
Article
em En
| MEDLINE
| ID: mdl-24474628
ABSTRACT
The pollen coat protects pollen grains from harmful environmental stresses such as drought and cold. Many compounds in the pollen coat are synthesized in the tapetum. However, the pathway by which they are transferred to the pollen surface remains obscure. We found that two Arabidopsis thaliana ATP binding cassette transporters, ABCG9 and ABCG31, were highly expressed in the tapetum and are involved in pollen coat deposition. Upon exposure to dry air, many abcg9 abcg31 pollen grains shriveled up and collapsed, and this phenotype was restored by complementation with ABCG9proGFPABCG9. GFP-tagged ABCG9 or ABCG31 localized to the plasma membrane. Electron microscopy revealed that the mutant pollen coat resembled the immature coat of the wild type, which contained many electron-lucent structures. Steryl glycosides were reduced to about half of wild-type levels in the abcg9 abcg31 pollen, but no differences in free sterols or steryl esters were observed. A mutant deficient in steryl glycoside biosynthesis, ugt80A2 ugt80B1, exhibited a similar phenotype. Together, these results indicate that steryl glycosides are critical for pollen fitness, by supporting pollen coat maturation, and that ABCG9 and ABCG31 contribute to the accumulation of this sterol on the surface of pollen.
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Base de dados:
MEDLINE
Assunto principal:
Pólen
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Arabidopsis
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Transportadores de Cassetes de Ligação de ATP
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Proteínas de Arabidopsis
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Glicosídeos
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article