Molecular and physiological responses in roots of two full-sib poplars uncover mechanisms that contribute to differences in partial submergence tolerance

Abstract

Poplar is a major afforestation tree species in flood-prone areas. Here, we compared molecular and physiological responses in the roots of two full-sib poplar clones, LS1 (flood-tolerant) and LS2 (flood-susceptive), subjected to stagnant flooding using transcript and metabolite profiling. LS1 displayed less phenotypic damage and superior leaf gas exchange and plant growth compared with those of LS2. We concluded that three characteristics might contribute to the differences in flood tolerance between LS1 and LS2. First, fermentation was initiated through lactic dehydrogenation in LS1 roots under flooding and subsequently dominated by alcohol fermentation. However, lactic dehydrogenase was persistently active in flooded LS2. Second, 13 differentially expressed genes associated with energy and O2 consumption processes under soil flooding had lower transcript levels in LS1 than those in LS2, which might contribute to better energy-/O2-saving abilities and behaviours in flood-tolerant LS1 than those in flood-susceptible LS2 under hypoxic stress. Third, LS1 possessed increased reactive oxygen species scavenging abilities compared with those of LS2 under edaphic flooding. Our data are a valuable contribution to understanding the mechanisms involved in the flood tolerance of poplar.

Understanding physiological and molecular mechanisms of Populus deltoides ‘DanHongYang’ tolerance to waterlogging by comparative transcriptome analysis

“…This finding means that the roots of P. deltoides 'DHY' can reduce the release of ethylene and increase the plants' tolerance to waterlogging stress by downregulating the expression of the above genes in waterlogged conditions. Role of sugar in the waterlogging tolerance of P. deltoides 'DHY' Many studies have found that the content of soluble sugar in plants is significantly increased under waterlogging conditions, which is an adaptation and protection mechanism for adversity and provides energy under hypoxic conditions (Peng et al, 2018). This study also detected that the soluble sugar content in P. deltoides 'DHY' under waterlogged conditions was significantly higher than that of the control.…”

Waterlogging tolerance evaluation of fifteen poplar clones cultivated in the Jianghan Plain of China

“…On the 0, 15 th , 30 th , 45 th and 60 th day of waterlogging treatment, the 5 th fully expanded and mature leaf from the top of the stem of each clone was chosen to measure leaf gas exchange and chlorophyll fluorescence (Peng et al, 2018). For leaf gas exchange measurement, four plants per clone per treatment were measured between 9:00 am.…”

“…Poplar (Populus L.) is one of the most important tree species for afforestation in these areas due to its characteristics of strong waterlogging resistance, rapid growth and broad applications. However, long-term waterlogging stress still adversely affects the growth and survival of poplar seriously (Peng et al, 2018). Under waterlogging stress, due to the lack of oxygen supply to roots, plants often present the phenomenon of leaf chlorosis and abscission, root rotting, photosynthetic capacity decline and so on, which leads to slow growth and even death, coupled with a huge loss of wood yield and ecological function (He et al, 2018;Zhao et al, 2019;Yan et al, 2019).…”

Responses of physiological activities and lateral root anatomical structure of Cercis glabra to waterlogging stress

“…Activities of antioxidant enzymes in plants under waterlogging stress are usually regarded as indicators of tolerance of genotypes against waterlogging stress (Qi et al, 2019). The SOD, POD, and CAT activities increase, causing ROS scavenging under waterlogging stress (Faseela et al, 2018;Peng et al, 2018).…”