Unraveling rice tolerance mechanisms against Schizotetranychus oryzae mite infestation

Abstract

Infestation of Schizotetranychus oryzae (Acari: Tetranychidae) causes great losses in rice productivity. Infestation in Puitá INTA-CL cultivar reduced the number of seeds/plant, percentage of full seeds, 1,000 seeds weight, and seed length, whereas infestation in IRGA423 increased 1,000 seeds weight and seed length. Reduction in seed weight/plant caused by infestation was higher in Puitá INTA-CL than IRGA423. Thus, Puitá INTA-CL was established as susceptible, and IRGA423 as tolerant to S. oryzae infestation. Photosynthetic parameters were less affected by infestation in IRGA423 than in Puitá INTA-CL. Infestation also caused accumulation of H2O2, decreased cell membrane integrity and accelerated senescence in leaves of Puitá INTA-CL, while leaves of IRGA423 presented higher levels of phenolics compounds. Using proteomic analysis, we identified proteins related to plant defense, such as jasmonate synthesis, and related to other mechanisms of tolerance such as oxidative stress, photosynthesis, and DNA structure maintenance, more abundant in IRGA423 after seven days of infestation. We detected higher levels of silicon (as amorphous silica cells) in leaves of infested IRGA423 plants compared to Puitá INTA-CL, an element previously linked to plant defense. Our data shows that IRGA423 presents tolerance to S. oryzae infestation, and that multiple mechanisms might be employed by this cultivar.