Light Deficiency Inhibits Growth by Affecting Photosynthesis Efficiency as well as JA and Ethylene Signaling in Endangered Plant Magnolia sinostellata

Abstract

The endangered plant Magnolia sinostellata largely grows in the understory of forest and suffers light deficiency stress. It is generally recognized that the interaction between plant development and growth environment is intricate; however, the underlying molecular regulatory pathways by which light deficiency induced growth inhibition remain obscure. To understand the physiological and molecular mechanisms of plant response to shading caused light deficiency, we performed photosynthesis efficiency analysis and comparative transcriptome analysis in M. sinostellata leaves, which were subjected to shading treatments of different durations. Most of the parameters relevant to the photosynthesis systems were altered as the result of light deficiency treatment, which was also confirmed by the transcriptome analysis. Gene Ontology and KEGG pathway enrichment analyses illustrated that most of differential expression genes (DEGs) were enriched in photosynthesis-related pathways. Light deficiency may have accelerated leaf abscission by impacting the photosynthesis efficiency and hormone signaling. Further, shading could repress the expression of stress responsive transcription factors and R-genes, which confer disease resistance. This study provides valuable insight into light deficiency-induced molecular regulatory pathways in M. sinostellata and offers a theoretical basis for conservation and cultivation improvements of Magnolia and other endangered woody plants.

Dark-Induced Effects on Pollen Development and HvGAMYB Expression in Spring Barley (<em>Hordeum vulgare</em> L.) Genotypes with Contrasting Drought Tolerance

“…In the experiment with temporary light deprivation, no significant effects of different water conditions were recorded, which suggests that the dark stress affected traits associated with spike fertility and contributed to the limitation of drought effects on spike morphology. Like several previous studies [69,70] demonstrating the negative impact of light distortion on the vegetative and generative cycle of plant development and other different aspects of plant biology [71,72], the present study also revealed that temporary light deficiency is a stronger stressor for seed development than drought occurrence. Interestingly, the drought conditionapplied in both Exp 1 and Exp 2 -contributed positively to FSm with increased values recorded for CamB.…”

Identification of potential light deficiency response regulators in endangered species Magnolia sinostellata

“…S1). Moreover, the net photosynthetic rate (Pn) and photochemical efficiency (Fv/Fm) declined obviously during the treatment, indicating that photosynthesis ability of M. sinostellata impaired 42 .…”

“…Leaves and seedlings of M. sinostellta gradually wilt under light deficiency treatment, and severe leaf abscission was observed, which was distinct from low light responses of module plants such as Arabidopsis 48 and rice 46 . Photosynthesis is essential for plant growth and development, and key photosynthetic indicators Pn and Fv/Fm were both decreased significantly in M. sinostellta 42 .…”

Conceptualizing Multiple Stressors and Their Consequences in Agroforestry Systems

“…Leaf expansion was restricted in Glycine max and Zea mays growing in the shade, which had an impact on seed yield [45]. In the case of vegetable crops such as tomato, cucumber, and eggplant, seedlings often develop abnormally under low light circumstances, resulting in lower yields in the field [17]. Phytochromes (PHY), which sense changes in both light intensity and quality, can sense changes in the light under canopy shade [46].…”