Expression patterns of terpene biosynthesis-related genes and resin production analysis in seedlings of Pinus elliottii Engelm

Abstract

As sessile organisms, plants must rely on a diverse array of chemical and physiological defenses to avoid and/or tolerate abiotic and biotic stresses. Pinaceae species produce resin rich in defensive terpenes which are exploited by industry. In order to identify young plants of Pinus elliottii (slash pine) that produce a higher quantity of resin, three different methodologies were tested to measure this potential in plants previously known to synthesize high and low quantities of resin. Resin exuded after bark removal and application of a chemical stimulant (methyl jasmonate) was quantified in parallel with qRT-PCR evaluations of transcriptional changes of genes related to the synthesis of terpenes and ethylene-responsive transcription factors. In addition, a gravimetric analysis of the resin content in brachyblasts was performed. The first two approaches proved to faithfully reflect the seedling’s capacity to yield resin, since consistent differences in resin weight and corresponding level of expression of several of the genes examined were observed for the two contrasting phenotypes. On the other hand, brachyblast resin gravimetry did not show significant difference between the phenotypes. To sum up, both resin weighing after bark removal and terpene and ethylene related gene expression properly reflected resin yield capacity, which may be useful for earlier selection of elite individuals to establish superresinous forests aiming at supplying the resin industry. In addition, resin production seems to be regulated at least partially by transcriptional activity in young slash pine trees.