Unraveling Rice Tolerance Mechanisms Against Schizotetranychus oryzae Mite Infestation

Abstract

Rice is the staple food for over half of the world’s population. Infestation of Schizotetranychus oryzae (Acari: Tetranychidae) causes great losses in rice productivity. To search for rice genotypes that could better tolerate S. oryzae infestation, we evaluated morphological and production parameters in Brazilian cultivars, and identified two cultivars with contrasting responses. Leaf damage during infestation was similar for all cultivars. However, infestation in Puitá INTA-CL resulted in reduction in the number of seeds per plant, percentage of full seeds, weight of 1,000 seeds, and seed length, whereas infestation in IRGA 423 increased weight of 1,000 seeds and seed length. Reduction in seed weight per plant caused by infestation was clearly higher in Puitá INTA-CL (62%) compared to IRGA 423 (no reduction detected), thus Puitá INTA-CL was established as susceptible, and IRGA 423 as tolerant to S. oryzae infestation. Photosynthetic parameters were less affected by infestation in IRGA 423 than in Puitá INTA-CL, evidencing higher efficiency of energy absorption and use. S. oryzae infestation also caused accumulation of H2O2, decreased cell membrane integrity (indicative of cell death), and accelerated senescence in leaves of Puitá INTA-CL, while leaves of IRGA 423 presented higher levels of total phenolics compounds. We performed proteomics analysis of Puitá INTA-CL and IRGA 423 leaves after 7 days of infestation, and identified 60 differentially abundant proteins (28 more abundant in leaves of Puitá INTA-CL and 32 in IRGA 423). 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, together with energy production and general metabolic processes, were more abundant in IRGA 423. We also detected higher levels of silicon (as amorphous silica cells) in leaves of infested IRGA 423 plants compared to Puitá INTA-CL, an element previously linked to plant defense, indicating that it could be involved in tolerance mechanisms. Taken together, our data show that IRGA 423 presents tolerance to S. oryzae infestation, and that multiple mechanisms might be employed by this cultivar. These findings could be used in biotechnological approaches aiming to increase rice tolerance to mite infestation.

Reactive oxygen species metabolism and photosynthetic performance in leaves of Hordeum vulgare plants co-infested with Heterodera filipjevi and Aceria tosichella

“…The reduction of photosynthesis may be induced by either direct mesophyll damage and a significant reduction in stomatal conductance (Fadini et al 2004) or disorders in the transcription and translation of proteins associated with the photosynthetic apparatus (Schmitt et al 2014) or disruptions in the synthesis pathway of chlorophylls and carotenoids (Bronner et al 1991). It was shown that reduced photosynthesis efficiency in rice plants can be caused not only by a decrease in chlorophyll content (Buffon et al 2016(Buffon et al , 2018 but also by down-regulation of seven proteins synthesis related to NADPH production and thus to adenosine triphosphate and glucose synthesis (Blasi et al 2017). In the presented experiment, however, no significant differences were observed in the efficiency of photosynthesis (PN), transpiration (E), as well as in stomatal conductance (Gs) between barley plants inoculated and uninoculated with CCN and WCM.…”

“…All these limitations lead to generation of ROS, RNS and organic radicals causing irreversible destruction of the photosynthetic apparatus (Kalaji et al 2016;Tokarz et al 2020a). Kinetic of chl a fluorescence revealed that rice plants sensitive to mite feeding had a significantly lower number of open PSII RC (F 0 ) among all PSII RC (Vj) as well as significantly lower efficiency of trapped energy flux (TRo/ CSo) compared to resistant plants (Buffon et al 2018). At the same time, sensitive cultivars dissipated more intensely part of the trapped energy (Dio/RC) (Buffon et al 2018).…”

“…Kinetic of chl a fluorescence revealed that rice plants sensitive to mite feeding had a significantly lower number of open PSII RC (F 0 ) among all PSII RC (Vj) as well as significantly lower efficiency of trapped energy flux (TRo/ CSo) compared to resistant plants (Buffon et al 2018). At the same time, sensitive cultivars dissipated more intensely part of the trapped energy (Dio/RC) (Buffon et al 2018). Barley plants examined in this work, regardless of kind of pest inoculation, were characterized by the same efficiency of trapping and transporting radiation to PSII RC as control plants.…”

Oryza sativa cv. Nipponbare and Oryza barthii as Unexpected Tolerance and Susceptibility Sources Against Schizotetranychus oryzae (Acari: Tetranychidae) Mite Infestation

“…The level of damage caused by S. oryzae was analyzed from V10-13 stage until the plants reached the final stage of reproductive development (panicle maturity, R9 stage; Counce et al, 2000 ). Evaluation of damage in the abaxial and adaxial faces of leaves was based on a classification of four infestation levels: Level 1: control condition, without any sign of infestation; Level 2: early infested (EI) leaves, 10–20% of damaged leaf area, average of 168 h of exposure to the mite; Level 3: intermediate infested (II) leaves, 40–50% of damaged leaf area, average of 360 h; and Level 4: late infested (LI) leaves, more than 80% of damaged leaf area, average of 720 h, according to Buffon et al (2018) .…”

“…Most of these losses (13–16%) occur in the field before harvesting, and losses are most often described in developing countries ( Culliney, 2014 ). One of the arthropods that attack rice crops in Brazil, and has been reported in other South American countries, is Schizotetranychus oryzae Rossi de Simons mite species, which can cause more than 60% loss in rice grain yield ( Buffon et al, 2018 ). An interesting strategy for reducing these losses is the search for mite-tolerant cultivars, as these plants tolerate mite infestation and maintain grain yield without the need to apply acaricides ( Sperotto et al, 2018a ).…”