Germination of Pisum sativum L. Seeds Is Associated with the Alternative Respiratory Pathway

Abstract

Germination is a complex process that begins with rapid water uptake and a marked increase in oxygen consumption rate from initiation of aerobic respiration. The mitochondrial electron transport chain (ETC) in plants is a critical cellular respiratory system that has two different pathways: the cytochrome oxidase (COX) pathway and the alternative oxidase (AOX) pathway. The AOX enzyme plays a crucial role in energy production as well as in stress response. An AOX gene family study in Pisum sativum revealed three AOX genes (PsAOX). Transcript accumulation analysis revealed the involvement of all three PsAOX members in pea seed germination, albeit with high genotype variation. Calorespirometry was used to monitor metabolic changes during a germination trial using inhibitors of both respiratory pathways and proved to be useful for distinguishing differing respiratory activity in different cultivars. This study offers valuable insights into the AOX family composition in P. sativum, as well as their role during seed germination.