Elucidation of transfer RNAs as stress regulating agents and the experimental strategies to conceive the functional role of tRNA-derived fragments in plants.

In plants, the transfer RNAs (tRNAs) exhibit their profound influence in orchestrating diverse physiological activities like cell growth, development, and response to several surrounding stimuli. The tRNAs, which were known to restrict their function solely in deciphering the codons, are now emerging as frontline defenders in stress biology. The plants that are constantly confronted with a huge panoply of stresses rely on tRNA-mediated stress regulation by altering the tRNA abundance, curbing the transport of tRNAs, fragmenting the mature tRNAs during stress. Among them, the studies on the generation of transfer RNA-derived fragments (tRFs) and their biological implication in stress response have attained huge interest. In plants, the tRFs hold stable expression patterns and regulate biological functions under diverse environmental conditions. In this review, we discuss the fate of plant tRNAs upon stress and thereafter how the tRFs are metamorphosed into sharp ammunition to wrestle with stress. We also address the various methods developed to date for uncovering the role of tRFs and their function in plants.

Phytophthora capsici infection causes dynamic alterations in tRNA modifications and their associated gene candidates in black pepper.

The efforts to signify the relevance of tRNA modifications were always within the limits of prokaryotes, humans, and some fewer model plant systems. The story of tRNA modifications in higher plants is still overlooked, especially in non-model spice crops. Stress causes alterations in tRNA modifications to facilitate the downstream functions of tRNAs. The present study was done to identify and better understand the fate of tRNA nucleoside modifications during biotic stress response in a widely used spice crop called Black pepper. We have uncovered the various tRNA nucleoside modifications present in black pepper. Methylations were the predominant nucleoside modifications in black pepper tRNAs. Furthermore, the different methyltransferase gene candidates implicated in catalyzing tRNA nucleoside methylations in black pepper were also identified. The LC-MS profile showed that certain tRNA nucleoside modifications showed varied abundance upon P. capsici infection. The N4-acetylcytidine (ac4C) nucleoside modification has shown a constant hike at 24 and 48 hpi. At the same time, some nucleoside modifications have exhibited a time-dependent abundance. Altogether our study suggests that tRNA modifications and the expression of associated enzymes are altered during biotic stress regulation.