Gene co-expression modulating terpene metabolism is associated with
plant anti-herbivore defence during initial flowering stages
Abstract
To protect themselves from herbivore attacks, especially during early
developmental stages, plants produce volatiles possessing various
ecological and physiological functions. Here, we identified three genes
cloned from Lavandula angustifolia. These genes, designated as LaTPS7,
LaTPS8, and LaCYP71D582, were hypothesized to be active in plant defense
during early developmental stages. The in-vitro assays showed LaTPS7
produced eight compounds including camphene, myrcene, limonene etc. and
LaTPS8 catalyzed nine volatiles from α-pinene, sylvestrene to fenchol
etc. using geranyl diphosphate (GPP) and nerolidyl diphosphate (NPP) as
substrate separately. However, LaTPS7 present in plastids only,
synthesized limonene within Nicotiana benthamiana. Limonene was then
converted into carveol by LaCYP71D582 present in the endoplasmic
reticulum. LaTPS8, also located in plastids, synthesized α-pinene and
sylvestrene. Odour response of aphids (Myzus persicae) and ladybugs
(Harmonia axyridis) showed that volatiles from transgenic tobacco leaves
repelled aphids and attracted ladybugs. LaTPS7 promoter GUS stain assay
in Arabidopsis thaliana showed that LaTPS7 displayed a wound-induced
expression in leaves. Together, our findings show that these compounds
and gene-expression pattern played important roles in protecting plants
during vulnerable stages. More practically, these plant tactics can be
exploited in agriculture to decrease the use of insecticides, thereby
contributing to improved human and environmental health.