AUTHOR=Pereira Juliana A. , Yu Fahong , Zhang Yanping , Jones Jeffrey B. , Mou Zhonglin 

TITLE=The Arabidopsis Elongator Subunit ELP3 and ELP4 Confer Resistance to Bacterial Speck in Tomato

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.01066

DOI=10.3389/fpls.2018.01066

ISSN=1664-462X

ABSTRACT=<p>Although production of tomato (<italic>Solanum lycopersicum</italic>) is threatened by a number of major diseases worldwide, it has been difficult to identify effective and durable management measures against these diseases. In this study, we attempted to improve tomato disease resistance by transgenic overexpression of genes encoding the <italic>Arabidopsis thaliana</italic> Elongator (AtELP) complex subunits AtELP3 and AtELP4. We show that overexpression of <italic>AtELP3</italic> and <italic>AtELP4</italic> significantly enhanced resistance to tomato bacterial speck caused by the <italic>Pseudomonas syringae</italic> pv. <italic>tomato</italic> strain J4 (<italic>Pst</italic> J4) without clear detrimental effects on plant growth and development. Interestingly, the transgenic plants exhibited resistance to <italic>Pst</italic> J4 only when inoculated through foliar sprays but not through infiltration into the leaf apoplast. Although this result suggested possible involvement of stomatal immunity, we found that <italic>Pst</italic> J4 inoculation did not induce stomatal closure and there were no differences in stomatal apertures and conductance between the transgenic and control plants. Further RNA sequencing and real-time quantitative PCR analyses revealed a group of defense-related genes to be induced to higher levels after infection in the <italic>AtELP4</italic> transgenic tomato plants than in the control, suggesting that the enhanced disease resistance of the transgenic plants may be attributed to elevated induction of defense responses. Additionally, we show that the tomato genome contains single-copy genes encoding all six Elongator subunits (SlELPs), which share high identities with the AtELP proteins, and that <italic>SlELP3</italic> and <italic>SlELP4</italic> complemented the <italic>Arabidopsis Atelp3</italic> and <italic>Atelp4</italic> mutants, respectively, indicating that the function of tomato Elongator is probably conserved. Taken together, our results not only shed new light on the tomato Elongator complex, but also revealed potential candidate genes for engineering disease resistance in tomato.</p>