Acclimation Strategy of Masson Pine (Pinus massoniana) by Limiting Flavonoid and Terpenoid Production under Low Light and Drought

Abstract

Low light and drought often limit the growth and performance of Masson pines (Pinus massoniana) in the subtropical forest ecosystem of China. We speculated that stress-induced defensive secondary metabolites, such as flavonoids and terpenoids, might influence the growth of Masson pines, considering the existence of tradeoffs between growth and defense. However, the mechanisms of Masson pines responsive to low light and drought at the levels of these two metabolites remain unclear. In the present work, the compositions of flavonoids and terpenoids, as well as their biosynthetic pathways, were revealed through metabolome and transcriptome analyses, respectively, coupled with a study on carbon allocation using a 13CO2-pulse-labeling experiment in two-year-old seedlings under low light (LL), drought (DR), and their combined stress (DL) compared to a control (CK). A total of 35 flavonoids and derivatives (LL vs. CK: 18; DR vs. CK: 20; and DL vs. CK: 18), as well as 29 terpenoids and derivatives (LL vs. CK: 23; DR vs. CK: 13; and DL vs. CK: 7), were differentially identified in the leaves. Surprisingly, most of them were decreased under all three stress regimes. At the transcriptomic level, most or all of the detected DEGs (differentially expressed genes) involved in the biosynthetic pathways of flavonoids and terpenoids were downregulated in phloem and xylem under stress treatments. This indicated that stress treatments limited the production of flavonoids and terpenoids. The reduction in the 13C allocation to stems might suggest that it is necessary for maintaining the growth of Masson pine seedlings at the whole-plant level by attenuating energetic resources to the biosynthetic pathways of flavonoids and terpenoids when facing the occurrence of adverse environments. Our results provide new insight into understanding the acclimation strategy of Masson pines or other conifers in adverse environments.

The metabolomics and transcriptomics of Atraphaxis bracteata reveal age‐related molecular alterations under naturally high temperature and drought conditions

“…Exposure to abiotic stress induced the accumulation of flavonoids, while excessive stress was shown to reduce the content of flavonoids (Guo et al 2021, Ma et al 2014). Certain DEGs involved in the flavonoid pathway were down‐regulated in response to abiotic stress (Shi et al 2022, Yang et al 2020). Chalcone synthase ( CHS ) is the key enzyme in the flavonoid biosynthetic pathway and often functions with chalcone isomerase ( CHI ) in response to stress (Deng et al 2014, Liu et al 2021, Ma et al 2014).…”

Characterization of 35 Masson pine (Pinus massoniana) half-sib families from two provinces based on metabolite properties

“…Also, extensive phenotypic differences have been found between families from different provinces based on the evaluation considering tree height, diameter at breast height (DBH), volume and other growth indicators (Liu et al, 2020;Zhang et al, 2022). Previous studies have focused more on the metabolism of Masson pine under different stress conditions (Shi et al, 2022;Wang et al, 2022). However, an in-depth analysis of the metabolic differences among Masson pine families of different provinces is lacking.…”

The Composite Physiological Response of Hydraulic and Photosynthetic Traits and Nonstructural Carbon in Masson Pine Seedlings to Drought Associated with High Temperature

“…Despite the robust adaptability of Masson pine and the rich annual precipitation in its distribution areas, this species still faces the mortality risk caused by the recurrent high temperatures in summer and low precipitation in subtropical regions [20], which may worsen the drought threat due to the above-mentioned climate change [7,11,15]. To explore the response of Masson pine to drought, previous studies have emphasized the leaf gas exchange [21], photosynthetic characteristics [22,23], biochemical parameters [18,24,25], hydraulic conductance and nonstructural carbon [17], root tip structure and volatile organic compounds [26], mycorrhizal fungus [22,25,27], and stress-induced defensive secondary metabolites (such as flavonoids and terpenoids [28]).…”