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Research article2022Peer reviewedOpen access

Adaptive strategies of Scots pine under shade: Increase in lignin synthesis and ecotypic variation in defense-related gene expression

Ranade, Sonali Sachin; Seipel, George; Gorzsas, Andras; Garcia-Gil, Maria Rosario

Abstract

Shade is a stressful condition for plants characterized by low Red:Far-Red (R:FR) ratio. The northern latitudes in Sweden daily receive more hours of FR-enriched light (twilight) or shade-like conditions compared to southern forests during the growing season. Scots pine (Pinus sylvestris L.) is a shade-intolerant species. Yet, it is well adapted to this latitudinal variation in light, which is evident by a northward increase in FR requirement to maintain growth. Shade adversely affects plant growth; it makes the plant weak and, therefore, susceptible to pathogen attack. Lignin is involved in plant protection against pathogen invasion mainly by forming a physical barrier. We studied lignin synthesis and expression of defense-related genes (growth-defense trade-offs) under a low R:FR (shade) ratio in Scots pine. A higher number of immunity/defense-related genes were up-regulated in response to shade in northern populations compared to southern ones, which can be viewed as a local adaptation to light quality for optimal growth and survival. Light quality regulates lignin metabolism; light stimulates lignin synthesis, while shade causes a decrease in lignin synthesis in most angiosperms. In contrast, Scots pine shows an increase in lignin synthesis supported by the higher expression of a few key genes in the lignin biosynthetic pathway, a novel finding reported by our study. These findings can be applied to future breeding strategies in forestry to produce disease-resilient trees.

Published in

Physiologia Plantarum
2022, Volume: 174, number: 5, article number: e13792Publisher: WILEY