Ning, Jing;
Moghe, Gaurav D.;
Leong, Bryan;
Kim, Jeongwoon;
Ofner, Itai;
Wang, Zhenzhen;
Adams, Christopher;
Jones, A. Daniel;
Zamir, Dani;
Last, Robert L.
A Feedback-Insensitive Isopropylmalate Synthase Affects Acylsugar Composition in Cultivated and Wild Tomato
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Media type:
E-Article
Title:
A Feedback-Insensitive Isopropylmalate Synthase Affects Acylsugar Composition in Cultivated and Wild Tomato
Contributor:
Ning, Jing;
Moghe, Gaurav D.;
Leong, Bryan;
Kim, Jeongwoon;
Ofner, Itai;
Wang, Zhenzhen;
Adams, Christopher;
Jones, A. Daniel;
Zamir, Dani;
Last, Robert L.
imprint:
American Society of Plant Biologists, 2015
Description:
<p>Acylsugars are insecticidal specialized metabolites produced in the glandular trichomes of plants in the Solanaceae family. In the tomato clade of the<italic>Solanum</italic>genus, acylsugars consist of aliphatic acids of different chain lengths esterified to sucrose, or less frequently to glucose. Through liquid chromatography-mass spectrometry screening of introgression lines, we previously identified a region of chromosome 8 in the<italic>Solanum pennellii</italic>LA0716 genome (IL8-1/8-1-1) that causes the cultivated tomato<italic>Solanum lycopersicum</italic>to shift from producing acylsucroses with abundant 3-methylbutanoic acid acyl chains derived from leucine metabolism to 2-methylpropanoic acid acyl chains derived from valine metabolism. We describe multiple lines of evidence implicating a trichome-expressed gene from this region as playing a role in this shift.<italic>S. lycopersicum</italic>M82<italic>SlIPMS3</italic>(Solyc08g014230) encodes a functional end product inhibition-insensitive version of the committing enzyme of leucine biosynthesis, isopropylmalate synthase, missing the carboxyl-terminal 160 amino acids. In contrast, the<italic>S. pennellii</italic>LA0716<italic>IPMS3</italic>allele found in IL8-1/8-1-1 encodes a nonfunctional truncated IPMS protein. M82 transformed with an<italic>SlIPMS3</italic>RNA interference construct exhibited an acylsugar profile similar to that of IL8-1-1, whereas the expression of<italic>SlIPMS3</italic>in IL8-1-1 partially restored the M82 acylsugar phenotype. These<italic>IPMS3</italic>alleles are polymorphic in 14<italic>S. pennellii</italic>accessions spread throughout the geographical range of occurrence for this species and are associated with acylsugars containing varying amounts of 2-methylpropanoic acid and 3-methylbutanoic acid acyl chains.</p>