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Title: Trichome formation and insect tolerance in tomato

Wei Deng

Chongqing University, China

Biography

Dr. Deng studied horticulture at the Southwest University, China and graduated as bachelor in 2000. He received his PhD degree in 2006 at Department of Plant Science, University of Connecticut, USA and Southwest University, China. He is a postdoctoral fellow at Department of Agricultural, Food and Nutritional Science, University of Alberta, Canada from 2011 to 2012. Now, he is a professor at School of Life Science, Chongqing University, China. He has published more than 30 research articles in SCI journals.

Abstract

Tomato trichomes, with unicellular and multicellular types, function as mechanical and chemical barrier against pests. Knock-down and over-expressed lines of SlARF4 were obtained to study the function in trichome formation in tomato. SlARF4-up-regulated plants exhibited increased density of type I, V and VI trichomes, whereas down-regulation of SIARF4 decreased density of type I, V and VI trichomes, indicating SlARF4 positively regulated the formation of unicellular and multicellular trichomes in tomato. Over-expression of SlARF4 increase the excretion of α-terpinene, β-phellandrene, γ-elemene, β-caryophyllene and α-humulene, and confers tolerance to spider mites. Down-regulation of SlARF4 decreased the terpenoid excretion and cause susceptibility to spider mites. Knock-down of SlTHM1 gene increase the density of type I and VI trichomes of leaves, indicating SlTHM1 negatively regulates the multicellular trichome formation. SlTHM1 knock-down plants exhibited increased the terpenoid excretion and tolerance to spider mites. SlARF4 targets the AuxRE motif of SlTHM1 genes and inhibits its expression. Knock-down of SlMYB52 gene increase the density of type V trichomes, which demostartes SlMYB52 negatively regulates the unicellular trichome formation. SlARF4 targets the TGA motif of SlMYB52 gene and inhibits its expression. Moreover, SlTHM1 and SlMYB52 target the promoter of SlCycB2 gene and increase its expression. Taken together, our results prove the SlARF4-SlTHM1/SlMYB52-SlCycB2 cascade in transcriptional regulation of the formation of unicellular and multicellular trichomes in tomato. Our results also provide a novel strategy for insect resistance in plants.