TabZIP74 Acts as a Positive Regulator in Wheat Stripe Rust Resistance and Involves Root Development by mRNA Splicing.

Basic leucine zipper (bZIP) membrane-bound transcription factors (MTFs) play important roles in regulating plant growth and development, abiotic stress responses, and disease resistance. Most bZIP MTFs are key components of signaling pathways in endoplasmic reticulum (ER) stress responses. In this study, a full-length cDNA sequence encoding bZIP MTF, designated , was isolated from a cDNA library of wheat near-isogenic lines of Taichung29*6/ inoculated with an incompatible race CYR32 of f. sp. (). Phylogenic analysis showed that is highly homologous to in maize and in rice. The mRNA of was predicted to form a secondary structure with two kissing hairpin loops that could be spliced, causing an open reading frame shift immediately before the hydrophobic region to produce a new TabZIP74 protein without the transmembrane domain. infection and the abiotic polyethylene glycol (PEG) and abscisic acid (ABA) treatments lead to mRNA splicing in wheat seedling leaves, while both spliced and unspliced forms in roots were detected. In the confocal microscopic examination, TabZIP74 is mobilized in the nucleus from the membrane of tobacco epidermal cells in response to wounding. Knocking down with barley stripe mosaic virus-induced gene silencing (BSMV-VIGS) enhanced wheat seedling susceptibility to stripe rust and decreased drought tolerance and lateral roots of silenced plants. These findings demonstrate that mRNA is induced to splice when stressed by biotic and abiotic factors, acts as a critically positive regulator for wheat stripe rust resistance and drought tolerance, and is necessary for lateral root development.