Abstract
Polyploidy impacts the diversity of plant species, giving riseto novel phenotypes and leading to ecological diversification. In order to observe adaptive and evolutionary capacities of polyploids, we compared the growth, primarymetabolism and transcriptomic expression level in theleaves of the newly formed allotetraploid Coffea arabicaspecies compared with its two diploid parental species(Coffea eugenioides and Coffea canephora), exposed to fourthermal regimes (TRs; 18–14, 23–19, 28–24 and 33–29C).The growth rate of the allopolyploid C. arabica was similarto that of C. canephora under the hottest TR and that of C.eugenioides under the coldest TR. For metabolite contentsmeasured at the hottest TR, the allopolyploid showed similar behavior to C. canephora, the parent which tolerateshigher growth temperatures in the natural environment.However, at the coldest TR, the allopolyploid displayedhigher sucrose, raffinose and ABA contents than those ofits two parents and similar linolenic acid leaf compositionand Chl content to those of C. eugenioides. At the gene expression level, few differences between the allopolyploid andits parents were observed for studied genes linked tophotosynthesis, respiration and the circadian clock, whereasgenes linked to redox activity showed a greater capacity ofthe allopolyploid for homeostasis. Finally, we found that theoverall transcriptional response to TRs of the allopolyploidwas more homeostatic compared with its parents. Thisbetter transcriptional homeostasis of the allopolyploid C.arabica afforded a greater phenotypic homeostasis whenfaced with environments that are unsuited to the diploidparental species