Diversification of Biscutella ser. Biscutella (Brassicaceae) followed post-Miocene geologic and climatic changes in the Mediterranean basin

Indexing Resilience to Heat and Drought Stress in the Wild Relatives of Rapeseed-Mustard

Wild species are weedy relatives and progenitors of cultivated crops, usually maintained in their centres of origin. They are rich sources of diversity as they possess many agriculturally important traits. In this study, we analysed 25 wild species and 5 U triangle species of Brassica for their potential tolerance against heat and drought stress during germination and in order to examine the early seedling stage. We identified the germplasms based on the mean membership function value (MFV), which was calculated from the tolerance index of shoot length, root length, and biochemical analysis. The study revealed that B. napus (GSC-6) could withstand high temperatures and drought. Other genotypes that were tolerant to the impact of heat stress were B. tournefortii (RBT 2002), D. gomez-campoi, B. tournefortii (Rawa), L. sativum, and B. carinata (PC-6). C. sativa resisted drought but did not perform well when subjected to high temperatures. Tolerance to drought was observed in B. fruticulosa (Spain), B. tournefortii (RBT 2003), C. bursa-pastoris (late), D. muralis, C. abyssinica (EC694145), C. abyssinica (EC400058) and B. juncea (Pusa Jaikisan). This investigation contributes to germplasm characterization and the identification of the potential source of abiotic stress tolerance in the Brassica breeding programme. These identified genotypes can be potential sources for transferring the gene(s)/genomic regions that determine tolerance to the elite cultivars.

Angiosperms at the edge: Extremity, diversity, and phylogeny

A hallmark of flowering plants is their ability to invade some of the most extreme and dynamic habitats, including cold and dry biomes, to a far greater extent than other land plants. Recent work has provided insight to the phylogenetic distribution and evolutionary mechanisms which have enabled this success, yet needed is a synthesis of evolutionary perspectives with plant physiological traits, morphology, and genomic diversity. Linking these disparate components will not only lead to better understand the evolutionary parallelism and diversification of plants with these two strategies, but also to provide the framework needed for directing future research. We summarize the primary physiological and structural traits involved in response to cold- and drought stress, outline the phylogenetic distribution of these adaptations, and describe the recurring association of these changes with rapid diversification events that occurred in multiple lineages over the past 15 million years. Across these threefold facets of dry-cold correlation (traits, phylogeny, and time) we stress the contrast between (a) the amazing diversity of solutions flowering plants have developed in the face of extreme environments and (b) a broad correlation between cold and dry adaptations that in some cases may hint at deep common origins.