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Plant Physiol. 2004 Mar;134(3):1080-7. Epub 2004 Feb 19.

A novel endo-beta-mannanase gene in tomato LeMAN5 is associated with anther and pollen development.

Author information

  • 1Department of Horticulture, Oregon State University, Corvallis, Oregon 97331-7304, USA.

Abstract

Endo-beta-mannanase (EC 3.2.1.78) is involved in cell wall disassembly and the weakening of plant tissues by degrading mannan polymers in the cell walls. Endo-beta-mannanase genes are expressed in tomato (Lycopersicon esculentum) seeds (LeMAN1 and LeMAN2) and fruits (LeMAN3 and LeMAN4). A novel endo-beta-mannanase gene (termed LeMAN5) was found in the tomato genome by genome-walking PCR and bacterial artificial chromosome library screening. The 5'-upstream region of this endo-beta-mannanase gene contained four copies of the pollen-specific cis-acting elements POLLEN1LELAT52 (AGAAA). A GUS-reporter gene driven with the putative LeMAN5 promoter (-543 to +38) was activated in anthers and pollen of transgenic Arabidopsis, with the highest beta-glucuronidase activity detected in pollen. beta-Glucuronidase expression was detected in mature pollen retained in sporangia, discharged pollen, and elongating pollen tubes in transgenic Arabidopsis. Consistently, expression of LeMAN5 mRNA and endo-beta-mannnanase activity was detected in tomato anthers and pollen. In anthers, the highest mRNA expression and endo-beta-mannanase activity were detected during late stages of anther development, when pollen maturation occurred. Endo-beta-mannanase activity was present in discharged pollen, which was easily eluted in a buffer, indicating that the enzyme proteins are probably secreted from, and deposited on, the surface of pollen. These data suggest that the LeMAN5 endo-beta-mannanase is associated with anther and pollen development.

PMID:
14976239
[PubMed - indexed for MEDLINE]
PMCID:
PMC389932
Free PMC Article

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