Ectopic expression of mitochondrial gamma carbonic anhydrase 2 causes male sterility by anther indehiscence

authored by

Fernando Villarreal, Victoria Martín, Alejandro Colaneri, Nahuel González-Schain, Mariano Perales, Mariana Martín, Cristina Lombardo, Hans Peter Braun, Carlos Bartoli, Eduardo Zabaleta

Abstract

Plant mitochondria include gamma-type carbonic anhydrases (γCAs) of unknown function. In Arabidopsis, the γCAs form a gene family of five members which all are attached to the NADH dehydrogenase complex (complex I) of the respiratory chain. Here we report a functional analysis of gamma carbonic anhydrase 2 (CA2). The gene encoding CA2 is constitutively expressed in all plant organs investigated but it is ten fold induced in flowers, particularly in tapetal tissue. Ectopic expression of CA2 in Arabidopsis causes male sterility in transgenic plants. In normal anther development, secondary thickenings of the endothecial cell wall cause anthers to open upon dehydration. Histological analyses revealed that abnormal secondary thickening prevents anther opening in 35S::CA2 transgenic plants. CA2 abundance in transgenic plants is increased 2-3 fold compared to wild-type plants as revealed by Western blotting analyses. Moreover, abundance of other members of the CA family, termed CA3 and CAL2, is increased in transgenic plants. Oxygen uptake measurements revealed that respiration in transgenic plants is mainly based on NADH reduction by the alternative NADH dehydrogenases present in plant mitochondria. Furthermore, the formation of reactive oxygen species (ROS) is very low in transgenic plants. We propose that reduction in ROS inhibits H₂O₂ dependent lignin polymerization in CA2 over-expressing plants, thereby causing male sterility.

Organisation(s)

Institute of Plant Genetics

External Organisation(s)

CONICET
Universidad Nacional de La Plata

Type

Article

Journal

Plant molecular biology

Volume

70

Pages

471-485

No. of pages

15

ISSN

0167-4412

Publication date

27.03.2009

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Agronomy and Crop Science, Genetics, Plant Science

Electronic version(s)

https://doi.org/10.1007/s11103-009-9484-z (Access: Unknown)