The role of alternative oxidase in plant hypersensitive response

Abstract

The innate immune system of plants is crucial in defining the fate of a plant cell during plant–pathogen interactions. This response is often accompanied by a hypersensitive reaction leading to the death of a plant cell and restricted pathogen growth. Plant mitochondria, in this case, play a key role by maintaining a balance between cell respiration and reactive oxygen species formation. One of the key features of the hypersensitive response is the shift of the normal plant respiratory pathway to a special ‘alternative’ pathway. Plants contain an enzyme, alternative oxidase, for maintaining metabolic homeostasis of the cell. This energy dissipating respiration provides a branch in normal respiration by using ubiquinone to form water and heat, thus maintaining the energy status of the cell. Alternative oxidase is thought to minimize production of reactive oxygen species and can also function in ‘anti‐apoptotic’ machinery in plant cells. In this mini review, we briefly describe the alternative respiratory pathway and explain the role of alternative oxidase in important cellular processes, such as programmed cell death and the hypersensitive response.

The NEL Family of Bacterial E3 Ubiquitin Ligases

“…The T3SS is also essential for the elicitation of the hypersensitive response on non-host plants. This is a local defense reaction that induces necrosis of the infected tissue and prevents the multiplication of bacteria [ 33 ]. A genomic study on 140 strains identified more than 100 effectors, but only 16 were present in at least 95% of sequenced strains and were considered core effectors [ 34 ].…”

Modified Northern blot protocol for easy detection of mRNAs in total RNA using radiolabeled probes

“…Such prolonged washing can cause nonspecific and specific bound probes to be washdown from the membrane, which may be worse when detecting the expression of low expression genes. One of such examples is the detection of the expression of Aox1 , a gene expressed in low-copy number that encodes the mitochondrial alternative oxidase (AOX), which is a regulatory component embedded in the inner face of the mitochondrial inner membrane [ 21 ]. Successful detection of Aox1 transcripts by Northern blot analysis can be achieved in two ways: using larger amounts of total RNA (30 µg, e.g.…”

Impairment of Respiratory Chain Function and Involvement of Alternative Respiratory Pathway in Mitochondria of Potato Tubers Infected by Pectobacteriumcarotovorum subsp. carotovorum

“…Mitochondria play an important role in potato tuber in response to soft rot disease. The change in the mitochondrial respiratory pathway leads to efficient disease response and may protect the plant from pathogen invasion [ 15 ]. This study was conducted to observe the mitochondrial responses during the interaction between potato tubers and soft rot bacteria Pcc ., and especially the role of the AOXs in the mitochondrial respiratory chain.…”

“…In contrast to that of animal mitochondria, plant mitochondria possess a unique respiratory pathway, the cyanide-insensitive alternative pathway (AOXs) that is catalyzed by the alternative oxidase, which is located in the mitochondrial inner membrane and acts as a terminal oxidase in mitochondrial electron transport respiration [ 14 , 15 ]. During plant-pathogen interactions, the operation level of the AOXs in host plants are enhanced in response to pathogen attack [ 16 , 17 , 18 , 19 ].…”

“…Therefore, the study of the role of the AOXs on mitochondrial respiratory chain function during the interaction between potato tubers and Pcc. is critical to understanding more about the AOXs as valuable regulators of mitochondrial respiratory chain function during pathophysiological processes in potato tubers [ 15 ].…”