Transcriptome and gene expression analysis revealed mechanisms for producing high oleoresin yields from Simao pine (Pinus kesiya var. langbianensis)

Abstract

Simao pine (Pinus kesiya Royle ex Gordon var. langbianensis (A. Chev.) Gaussen) is an important oleoresin source in Yunnan Province, China. However, the molecular mechanisms of high oleoresin yield from Simao pine remain unclear. In this study, RNA-Seq was used to investigate the transcriptome of the species and compare the gene expression profiles of wounded bark from high and low oleoresin-yielding individuals, and the expression levels of genes in the methyl-erythritol 4-phosphate (MEP) pathway were detected by qPCR. A total of 1.41 billion reads were obtained and assembled into 68,881 unigenes from samples of the wounded bark of Simao pine. The KEGG analysis of differentially expressed genes showed that MEP pathway genes were obviously differentially expressed, while most genes in the mevalonate (MVA) pathway were not. The qPCR analysis showed that the MEP pathway gene expression of wounded bark from high oleoresin-yielding genotypes was higher than that of low oleoresin-yielding genotypes. The gene expression differences of 1-deoxy-D-xylulose-5-phosphate synthase (DXS), 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR), and geranylgeranyl pyrophosphate synthase (GGPPs) between high and low oleoresin-yielding genotypes were significant. This implies that DXS, HDR, and GGPPs play important roles in high oleoresin production in Simao pine.

QTL mapping for growth-related traits by constructing the first genetic linkage map in Simao pine

“…Two years later, a total of 9 full-sib families were obtained and grown at the farm of Pu'er city institute of forestry sciences (N 22• 47′/E 100• 59′) by harvesting, sowing and culturing the seedlings. Proceed to the next step, family 9 was selected as the mapping population for Simao pine genetic linkage map construction by analyzing population phenotypic variation and parent's genetic similarity coe cient (Wang et al, 2018). The parents for the mapping population were superior clone SM11 (maternal, with the characteristic of high resin content) and JG1 (paternal, with the aspect of rapid growth).…”

“…Compared with other conifer tree species, it has unique rapid growth characteristics that its branches can grow 2 or more rounds a year (Xu et al, 2012;Ou et al, 2016), and the timber is widely used in ber, furniture, and the building industry (Cai et al, 2017). Simao pine is not only a high commercial value plant for its higher turpentine output (Dong et al, 2009;Wang et al, 2018) but also essential tree species in the forest ecosystem for the function of biological carbon sequestration and water conservation (Wen et al, 2010;Zhu et al, 2016;Cao & Zhang, 2017;Li et al, 2017). However, its exploitation and utilization are constrained by relatively lacking genetic information (Cai et al, 2017).…”

QTL Mapping for Growth-Related Traits by Constructing the First Genetic Linkage Map in Simao pine

“…Two years later, totally 9 full-sib families were obtained and grown at the farm of Pu'er city institute of forestry sciences (N 22• 47′/E 100• 59′) by harvesting, sowing and culturing the seedlings. Family 9 was selected as the mapping population for Simao pine genetic linkage map construction by analysis of phenotypic variation for populations and genetic similarity coe cient among parents (Wang et al, 2018). The parents for mapping population were superior clone SM11 (maternal, with characteristic of high resin content) and superior clone JG1 (paternal, with characteristic of rapid growth) respectively.…”

“…Compared with other conifer tree species, it has unique rapid growth characteristics that its branches can grow 2 or more rounds a year (Xu et al, 2012;Ou et al, 2016), and its timber is widely used in ber, furniture, and the building industry (Cai et al, 2017). In addition, Simao pine is not only a high economical plant for its high turpentine output (Dong et al, 2009;Wang et al, 2018), but also an important species in forest ecosystem for the function of carbon sequestration biological and water conservation (Wen et al, 2010;Zhu et al, 2016;Cao & Zhang, 2017;Li et al, 2017). However, it's exploitation and utilization are constrained by relatively lacking the genetic information (Cai et al, 2017).…”