Abstract
Basic domain-leucine zipper (bZIP) transcription factor, one type of conserved gene family, plays an important role in plant development and stress responses. Although 77 MebZIPs have been genome-wide identified in cassava, their in vivo roles remain unknown. In this study, we analyzed the expression pattern and the function of two MebZIPs (MebZIP3 and MebZIP5) in response to pathogen infection. Gene expression analysis indicated that MebZIP3 and MebZIP5 were commonly regulated by flg22, Xanthomonas axonopodis pv. manihotis (Xam), salicylic acid (SA), and hydrogen peroxide (H2O2). Subcellular localization analysis showed that MebZIP3 and MebZIP5 are specifically located in cell nucleus. Through overexpression in tobacco, we found that MebZIP3 and MebZIP5 conferred improved disease resistance against cassava bacterial blight, with more callose depositions. On the contrary, MebZIP3- and MebZIP5-silenced plants by virus-induced gene silencing (VIGS) showed disease sensitive phenotype, lower transcript levels of defense-related genes and less callose depositions. Taken together, this study highlights the positive role of MebZIP3 and MebZIP5 in disease resistance against cassava bacterial blight for further utilization in genetic improvement of cassava disease resistance.
Highlights
The genus Xanthomonas is a kind of plant pathogen that infects a wide range of plant species, including rice, pepper, tomato, citrus, and Nicotiana benthamiana
Using quantitative real-time PCR, we found that the transcript levels of MebZIP3 and MebZIP5 were significantly regulated after flg22, Xanthomonas axonopodis pv. manihotis (Xam), salicylic acid (SA) and hydrogen peroxide (H2O2) treatments (Figures 1A,B)
After flg22 treatment, the transcript levels of MebZIP3 and MebZIP5 were down-regulated at 3 h, but largely up-regulated at 6 h
Summary
The genus Xanthomonas is a kind of plant pathogen that infects a wide range of plant species, including rice, pepper, tomato, citrus, and Nicotiana benthamiana. Xam is the causal pathogen of cassava bacterial blight, resulting in leaf wilting, shoot dieback, and stem vascular necrosis (McCallum et al, 2017). Cassava is one major tropical crop; its yield is seriously affected. MebZIP3/5 in Plant Disease Resistance by cassava bacterial blight (Pereiral et al, 2003; Camilo et al, 2005; Quintero et al, 2013; Muñoz-Bodnar et al, 2014). The molecular mechanism underlying cassava in response to bacterial blight is largely unknown, and the identification and utilization of disease-related genes are very limited. Some disease resistant cassava varieties have been identified (Boher and Verdier, 1994; Wydra et al, 2007), functional characterization of disease-related genes remains limited
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call