Physiological and transcriptomic responses of Mikania micrantha stem to shading yield novel insights into its invasiveness

• Published in: Biological invasions Vol. 23; no. 9; pp. 2927 - 2943
• Main Authors: Jiang, Zhaoyang, Wang, Yutao, Zheng, Yaping, Cai, Minling, Peng, Changlian, Li, Weihua
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-09-2021; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Developmental Biology; Ecology; Elongation; Freshwater & Marine Ecology; Gene expression; Genes; Invasive plants; Invasiveness; Life Sciences; Light; Light levels; Luminous intensity; Mikania micrantha; Molecular modelling; Original Paper; Photosynthesis; Physiology; Plant Sciences; Plasticity; Shading; Stems; Transcriptomes; Understory; Phytohormones; Light availability; Stem photosynthesis; Plasticity; Transcriptome
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-021-02546-z

The rapid stem elongation of the invasive weed
Mikania micrantha
in the forest understory is of vital significance for its successful invasion. To understand the physiological and molecular mechanisms for this process, here we comparatively investigated the physiological characteristics and transcriptome patterns of
M. micrantha
stem under low light (30%) and full light (100%) conditions. The results showed that
M. micrantha
stem had photosynthetic capacity, which was highly plastic to light intensities, constituting an indispensable part of the plastic response of
M. micrantha
to shading.
M. micrantha
had longer internodes, epidermal cells, and consequently longer stems under low light than full light conditions, which could proximally be attributed to phytohormone production and reduction of photoprotective substances as potential metabolic trade-off, as observed here under shading treatment. The transcriptome sequencing and qPCR verified the results from physiological investigation, and showed that under low light condition the expression levels of genes involved in photosynthesis (e.g.
MmPsaA
,
MmPsbO1
and
MmFd3
) were generally down-regulated in comparison to full light condition, as were genes related to the photoprotective substances synthesis (e.g.
MmCHS
, and
MmF3H1
) and the negative regulators of phytohormone (e.g.
MmAUX1, MmRR1
and
MmGAI
). It was concluded that the regulation of phytohormones and photoprotective substances are important material basis for the rapid elongation of
M. micrantha
stems with high plasticity, which facilitates the vine's invasiveness in the forest understory.