The tRNA-degradation pathway impacts the phenotype and metabolome of Arabidopsis thaliana: evidence from atipt2 and atipt9 knockout mutants

Abstract

Isopentenyltransferases (IPTs), including adenosine phosphate-isopentenyltransferases (ATP/ADP-IPTs and AMP-IPTs) and tRNA-isopentenyltransferases (tRNA-IPTs), are responsible for a rate-limiting step of cytokinin (CK) biosynthesis. tRNA-IPTs, which account for the synthesis of cis-zeatin (cZ)-type CKs, are less understood and often thought to play a housekeeping role or have low activity during plant growth and development. Here, two Arabidopsis tRNA-IPT knockout mutants, atipt2 and atipt9, with independent disturbance of the pathway leading to cisCKs were investigated at the phenotype and metabolite levels at four stages of plant development: rst leaf, in orescence, siliques, and mature seed. Phenotypic deviations were noted in rosette diameter, number of nonrosette leaves, shoot height, owering time, ower number, carotenoid content, trichome development, and above-ground fresh mass. Hormone pro ling by high-performance liquid chromatography -high resolution tandem mass spectrometry (HPLC-HRMS/MS) showed that the atipt2 mutant accumulates lower total cisCKs in the rst leaves and in siliques. The atipt9 mutant showed reduced total cisCKs in rst leaves, but, during silique development, it had higher levels of cisCKs in than those of the wild type (WT) plants. Additionally, metabolite detection was performed via an untargeted approach using HPLC-HRMS. A total of 33 signi cant features differing in abundance between ipt mutants and the WT were putatively identi ed based on database search. Matched metabolites included those that participate in hormone cross-talk, fatty acid synthesis, seed set and germination, and in stress acclimation. Evidence indicates that cisCK production is important for plant growth and development, in ways distinct from CKs produced from de novo pathway.

Unlocking Potentially Therapeutic Phytochemicals in Capadulla (Doliocarpus dentatus) from Guyana Using Untargeted Mass Spectrometry-Based Metabolomics

“…Metabolite extraction was performed as previously published [29]. Thirty mg of D. dentatus dried tissues were pre-weighed before the extraction.…”

“…Extracts from both D. dentatus ecotypes (i.e., red and white) were analyzed by LC-MS [29] with minor modifications. For an untargeted metabolomics analysis, the data were acquired using a Thermo Q-Exactive Orbitrap mass spectrometer (Thermo Scientific, San Jose, CA, USA) coupled to a Thermo Dionex Ultimate 3000 Liquid Chromatograph System (Thermo Scientific, San Jose, CA, USA).…”