AUTHOR=Dai Huaxin , Yang Jinpeng , Teng Lidong , Wang Zhong , Liang Taibo , Khan Waleed Amjad , Yang Ruiwei , Qiao Baoming , Zhang Yanling , Yang Chunlei 

TITLE=Mechanistic basis for mitigating drought tolerance by selenium application in tobacco (Nicotiana tabacum L.): a multi-omics approach

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1255682

DOI=10.3389/fpls.2023.1255682

ISSN=1664-462X

ABSTRACT=<p>The lack of irrigation water in agricultural soils poses a significant constraint on global crop production. In-depth investigation into microRNAs (miRNAs) has been widely used to achieve a comprehensive understanding of plant defense mechanisms. However, there is limited knowledge on the association of miRNAs with drought tolerance in cigar tobacco. In this study, a hydroponic experiment was carried out to identify changes in plant physiological characteristics, miRNA expression and metabolite profile under drought stress, and examine the mitigating effects of selenium (Se) application. The shoot dry weight of drought-stressed plants was approximately half (50.3%) of that in non-stressed (control) conditions. However, plants supplied with Se attained 38.8% greater shoot dry weight as compared to plants with no Se supply under drought stress. Thirteen miRNAs were identified to be associated with drought tolerance. These included 7 known (such as nta-miR156b and nta-miR166a) and 6 novel miRNAs (such as novel-nta-miR156-5p and novel-nta-miR209-5p) with the target genes of <italic>squamosa promoter-binding-like protein 4</italic> (<italic>SPL4</italic>), <italic>serine/threonine protein phosphatase 2A</italic> (<italic>PPP2A</italic>), <italic>cation/calcium exchanger 4-like</italic> (<italic>CCX4</italic>), <italic>extensin-1-like</italic> (<italic>EXT1</italic>) and <italic>reduced wall acetylation 2</italic> (<italic>RWA2</italic>). Further investigation revealed that the expression levels of <italic>Ext1</italic> and <italic>RWA2</italic> were significantly decreased under drought stress but increased with Se addition. Moreover, key metabolites such as catechin and N-acetylneuraminic acid were identified, which may play a role in the regulation of drought tolerance. The integrated analysis of miRNA sequencing and metabolome highlighted the significance of the novel-nta-miR97-5p- <italic>LRR-RLK</italic>- catechin pathway in regulating drought tolerance. Our findings provide valuable insights into the molecular mechanisms underlying drought tolerance and Se-induced stress alleviation in cigar tobacco.</p>