Evolutionary Understanding of Metacaspase Genes in Cultivated and Wild Oryza Species and Its Role in Disease Resistance Mechanism in Rice

Abstract

Metacaspases (MCs), a class of cysteine-dependent proteases found in plants, fungi, and protozoa, are predominately involved in programmed cell death processes. In this study, we identified metacaspase genes in cultivated and wild rice species. Characterization of metacaspase genes identified both in cultivated subspecies of Oryza sativa, japonica, and indica and in nine wild rice species was performed. Extensive computational analysis was conducted to understand gene structures, phylogenetic relationships, cis-regulatory elements, expression patterns, and haplotypic variations. Further, the haplotyping study of metacaspase genes was conducted using the whole-genome resequencing data publicly available for 4726 diverse genotype and in-house resequencing data generated for north-east Indian rice lines. Sequence variations observed among wild and cultivated rice species for metacaspase genes were used to understand the duplication and neofunctionalization events. The expression profiles of metacaspase genes were analyzed using RNA-seq transcriptome profiling in rice during different developmental stages and stress conditions. Real-time quantitative PCR analysis of candidate metacaspase genes in rice cultivars Pusa Basmati-1 in response to Magnaporthe oryzae infection indicated a significant role in the disease resistance mechanism. The information provided here will help to understand the evolution of metacaspases and their role under stress conditions in rice.

A Novel Allele Encoding 7-Hydroxymethyl Chlorophyll a Reductase Confers Bacterial Blight Resistance in Rice

“…Our results imply that increased activities of ROS scavenging enzymes could not lower the elevated H 2 O 2 accumulation. Lastly, we performed the expression analysis of several metacaspase (MC) genes, which are essential controllers of PCD [ 26 ]. The results revealed that seven MC genes, including OsMC1 , OsMC2, OsMC4, OsMC5, OsMC6, OsMC7 , and OsMC8 , were highly expressed in HM143 compared to WT, but no remarkable difference was detected in the expression pattern of 1 MC gene, i.e., OsMC3 between HM143 and WT ( Figure 1 G).…”

“…Additionally, JAmyb , OsNAC4 , and OsAPX1 genes that are enhanced during cell death were notably upregulated, suggesting that HCAR plays a vital role in modulating cell death [ 24 ]. In this study, cell death in OsHCAR was detected using TUNEL assay, an indicator of DNA fragmentation, which was reinforced by the upregulation of OsMCs genes which are essential regulators of PCD in plants [ 26 ]. H 2 O 2 is a significant by-product of beta-oxidation and functions as a cue particle to promote cell death.…”

Ecosystem services provided by freshwater macrophytes

“…Genetic resources are another type of ES produced by macrophytes. For example, genetic studies in cultivated and wild rice species have helped to identify disease resistance mechanisms (Bansal et al, 2020;Hada et al, 2020), with great potential to be used in breeding programs to reduce damage to varieties of rice. From this example, we expect that the same procedure can be employed for other macrophytes used as food by humans.…”

The Metacaspase TaMCA-Id Negatively Regulates Salt-Induced Programmed Cell Death and Functionally Links With Autophagy in Wheat

“…Although the caspases have not yet been found in plants, it has been reported that caspase-like enzymatic activity functions in many cell death pathways in plants (Luan et al, 2021 ). Nevertheless, metacaspase (MCA), a class of cysteine proteases present in plants, is structurally related to caspase and has caspase-like catalytic domain containing 20 kDa (p20) and 10 kDa (p10) subunits that are crucial for mediating PCD (Fagundes et al, 2015 ; Bansal et al, 2020 ). MCA includes type I and type II, according to its protein structure (Yao et al, 2020 ).…”