Studies on adaptive environmental responses in Himalayan Rhododendron arboreum

Abstract

Temperate plants acclimatize to survive freezing temperatures, which are otherwise newlineprerequisite in the initiation/transition of a developmental phase. The dominance of newlineRhododendron arboreum under a highly fluctuating Himalayan environment makes newlineit enticing for genetic structure and functional analysis. In the present study, newlinetranscript, small RNA and metabolome libraries from flowers and foliar tissues of newlinereproductive and vegetative seasons were analyzed. The high-quality paired-end newlinereads were assembled into 157,427 non-redundant transcripts and categorized newlinefunctionally based on gene ontology, pathway, and transcription factor database. newlineThe screening for molecular markers identified 35,419 SSR and 811 high-quality newlineSNPs. A comparison of transcript profiles for the vegetative and flowering season newlinetissues revealed that 12,577 unigenes with fluctuating expression were responsible newlinefor seasonal adaptations. Additional to the gene interaction networks, 421 ions newlineobtained from LC-MS were annotated to distinct pathways, especially secondary newlinemetabolites. Thirdly, 466 conserved and novel miRNAs, 442 precursors, and 27,139 newlinetargets were predicted and the miRNAs modulating circadian clock and reproductive newlinedevelopment were discussed further. Other than the genes, miRNAs, and newlinecompounds held for an active metabolism, signaling, development, and their newlineregulations, supplementary responses to abiotic/biotic stimuli were induced. A newlinemultifaceted response not only sponsored the climatic encounters but brought the newlineshift from vegetative to reproductive growth. The genome-wide profiling and the newlinespatiotemporal variation in mRNA and miRNA expression, as well as the nontargeted newlinemetabolome, will enhance the understanding of development and newlinetolerance strategies in high altitude tree species. newline