中文题名 / Chinese title: 维管形成层细胞多特征分析揭示老银杏树的长寿机制
英文题名 / English title: Multifeature analyses of vascular cambial cells reveal longevity mechanisms in old Ginkgo biloba trees.
作者 / Authors: Wang L, Cui J, Jin B, Zhao J, Xu H, Lu Z, Li W, Li X, Li L, Liang E, Rao X, Wang S, Fu C, Cao F, Dixon RA, Lin J.
期刊 / Journal: PNAS
年份 / Year: 2020
DOI: 10.1073/pnas.1916548117
论文链接 / Article: https://doi.org/10.1073/pnas.1916548117
摘要来源 / Abstract source: https://europepmc.org/article/MED/31932448

英文摘要原文 / Original English abstract
Aging is a universal property of multicellular organisms. Although some tree species can live for centuries or millennia, the molecular and metabolic mechanisms underlying their longevity are unclear. To address this, we investigated age-related changes in the vascular cambium from 15- to 667-y-old Ginkgo biloba trees. The ring width decreased sharply during the first 100 to 200 y, with only a slight change after 200 y of age, accompanied by decreasing numbers of cambial cell layers. In contrast, average basal area increment (BAI) continuously increased with aging, showing that the lateral meristem can retain indeterminacy in old trees. The indole-3-acetic acid (IAA) concentration in cambial cells decreased with age, whereas the content of abscisic acid (ABA) increased significantly. In addition, cell division-, cell expansion-, and differentiation-related genes exhibited significantly lower expression in old trees, especially miR166 and HD-ZIP III interaction networks involved in cambial activity. Disease resistance-associated genes retained high expression in old trees, along with genes associated with synthesis of preformed protective secondary metabolites. Comprehensive evaluation of the expression of genes related to autophagy, senescence, and age-related miRNAs, together with analysis of leaf photosynthetic efficiencies and seed germination rates, demonstrated that the old trees are still in a healthy, mature state, and senescence is not manifested at the whole-plant level. Taken together, our results reveal that long-lived trees have evolved compensatory mechanisms to maintain a balance between growth and aging processes. This involves continued cambial divisions, high expression of resistance-associated genes, and continued synthetic capacity of preformed protective secondary metabolites.

摘要依据的主要发现 / Findings based on the abstract
15至667年生银杏的形成层活性和激素随树龄变化，但防御基因表达与次生代谢物生产保持活跃；所采老树未表现明显整株衰老指标。
Trees aged fifteen to 667 years show age-related changes in cambial activity and hormones but maintain protective gene expression and secondary-metabolite production. Whole-plant senescence indicators were not evident in the sampled old trees.

摘要依据的结论 / Conclusions based on the abstract
长寿与补偿性生长和防御机制相关；该研究并不意味着单株树木不会死亡。
Long life is associated with compensatory growth and defense mechanisms; the study does not imply that individual trees are immortal.

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