Comparative physiological, ultrastructural and proteomic analyses reveal sexual differences in the responses of Populus cathayana under drought stress

Abstract

Drought is a major abiotic stress, limiting the survival and growth of young plants. However, little is known about sex-dependent responses to drought at the proteome level. In this study, we carried out investigations on comparative proteomics, combined with physiological and organelle structure analyses, in males and females of Populus cathayana Rehd. Three-month-old poplar cuttings were treated at 30% of field capacity and at 100% field capacity as a control in a greenhouse for 40 days. Drought greatly inhibited plant growth, damaged the photosynthetic system and destructed the structures of chloroplasts, mitochondria and cellular membranes. However, males suffered less from the adverse effects of drought than did females. Using 2-DE, 563 spots were detected, of which 64 spots displayed significant drought effect and 44 spots displayed a significant sex by drought interaction effect. The results suggest that the different responses to drought stress detected between the sexes have a close relationship to the changes in the expression of sex-dependent proteins, including, e.g. photosynthesis-related proteins, homeostasis-related proteins and stress response proteins. These proteins could contribute to a physiological advantage under drought, giving potential clues for understanding sexual differences in the performance of plants in different environments.

A morpho-physiological approach differentiates bread wheat cultivars of contrasting tolerance under cyclic water stress

“…Vacuolized chloroplasts with thylakoidal membrane distortions in mesophyll cells of sensitive apple (Malus hupehensis) leaves were described by Wang et al (2012a,b). Drought stressinduced destruction of chloroplast structures was also found in female poplar (Zhang et al, 2010). In our experiments, rapid or severe loss of cellular integrity was a hallmark of drought sensitivity.…”

Populus cathayana males exhibit more efficient protective mechanisms than females under drought stress

“…As the different reproduction costs, males and females have evolved different adaptive strategies to environmental stresses (Dawson and Bliss, 1989;Dawson and Ehleringer, 1993). Our previous studies have shown that there are different tolerance and sensitivity in male and female poplars to nitrogen deposition, photoperiod, heavy metals, sanity, chilling and rust disease (Zhao et al, 2009(Zhao et al, , 2011Chen et al, 2010a,b;Zhang et al, 2010aZhang et al, , 2011. In these studies, we found a common phenomenon that male poplars showed higher antioxidant enzyme activities than females under the above stresses.…”

“…These results suggest that sexually different responses in antioxidants are distinct. A previous proteome study also discovered that APX and peroxidase proteins exhibit a higher abundance in drought-stressed males than in drought-stressed females (Zhang et al, 2010a).…”

“…The appearance of plastoglobules in chloroplasts is usually considered as a symptom of senescence, since they are regarded as lipid droplets derived from thylakoid degradation (Ghosh et al, 2001;Dalla-Vecchia et al, 2005). Actually, previous studies have suggested that drought-stressed females exhibited higher malonaldehyde (MDA) content than drought-stressed males (Xu et al, 2008a;Chen et al, 2010b;Zhang et al, 2010a). Ultrastructurally, males appeared to have less seriously damaged chloroplasts under drought stress than did females, which may be another reason why drought-stressed males possessed higher P n than did drought-stressed females.…”

Sex-specific carbon and nitrogen partitioning under N deposition in Populus cathayana

“…In addition, recent literatures showed that both stress adaptive capacity and resource availability are two important factors affecting secondary sexual dimorphism. In general, females are more sensitive and poorer adaptive to stress conditions than males, which could be deduced from changes in physiology, biochemistry, transcriptome and proteome levels when plants are exposed to stress conditions (Dudley and Galen 2007;Chen et al 2010Chen et al , 2011Zhang et al 2010;Jiang et al 2012). On the other hand, resource availability may also influence distribution of dioecious plants.…”