Mitochondrial dynamics and mitophagy are necessary for proper invasive growth in rice blast

Abstract

Summary Magnaporthe oryzae causes blast disease, which is one of the most devastating infections in rice and several important cereal crops. Magnaporthe oryzae needs to coordinate gene regulation, morphological changes, nutrient acquisition and host evasion in order to invade and proliferate within the plant tissues. Thus far, the molecular mechanisms underlying the regulation of invasive growth in planta have remained largely unknown. We identified a precise filamentous‐punctate‐filamentous cycle in mitochondrial morphology during Magnaporthe –rice interaction. Interestingly, disruption of such mitochondrial dynamics by deletion of genes regulating either the mitochondrial fusion (MoFzo1) or fission (MoDnm1) machinery, or inhibition of mitochondrial fission using Mdivi‐1 caused significant reduction in M. oryzae pathogenicity. Furthermore, exogenous carbon source(s) but not antioxidant treatment delayed such mitochondrial dynamics/transition during invasive growth. In contrast, carbon starvation induced the breakdown of the mitochondrial network and led to more punctate mitochondria in vitro . Such nutrient‐based regulation of organellar dynamics preceded MoAtg24‐mediated mitophagy, which was found to be essential for proper biotrophic development and invasive growth in planta . We propose that precise mitochondrial dynamics and mitophagy occur during the transition from biotrophy to necrotrophy and are required for proper induction and establishment of the blast disease in rice.

NIK promotes metabolic adaptation of glioblastoma cells to bioenergetic stress

“…Mitochondria undergo dynamic morphological changes in response to environmental stress and nutrient availability has been shown to dictate mitochondrial morphology 7 , 21 , 43 . Our findings are consistent with previous studies demonstrating that nutrient starvation induces mitochondrial fission 44 – 46 and suggest that metabolic regulation of mitochondrial dynamics may be determined by NIK activity to promote metabolic reprogramming to OXPHOS and drive invasive growth. Indeed, analysis of RNA-seq data from the IVY Glioblastoma Atlas 47 revealed that genes regulating mitochondrial dynamics, including DRP1, as well as mitochondrial respiratory complexes are more highly expressed at the tumor leading edge compared to the tumor core (Supplementary Fig.…”

Dynamic Regulation of Peroxisomes and Mitochondria during Fungal Development

“…Nonetheless, further examination of mitophagy in M. oryzae revealed that the loss of Atg24 results in delayed appressorium infectivity and reduced growth of the invasive hyphae. In line with these findings, Atg24-dependent vacuolar degradation of mitochondria was observed during the initial stages of the plant infection [122]. These observations disclosed that Atg24-driven mitophagy is required for the establishment of the blast disease.…”

“…As for M. oryzae , Dnm1 is required for full virulence in the corn smut fungus Ustilago maydis [ 121 ]. Additionally, the deletion of the fusion machinery gene FZO1 also results in decreased infective growth and reduced appressoria penetration capability in M. oryzae [ 122 ].…”

DnmA and FisA Mediate Mitochondria and Peroxisome Fission, and Regulate Mitochondrial Function, ROS Production and Development in Aspergillus nidulans

“…The fact that during infection this fungus is exposed to high ROS levels, suggests that H 2 O 2 produced by the plant could induce mitochondrial fission. Carbon starvation has been proposed as the trigger of mitochondrial fragmentation under these conditions (Kou et al, 2019). However, both factors might contribute to this process.…”