Higher order polyploids exhibit enhanced desiccation tolerance in the grass Microchloa caffra.

Desiccation tolerance evolved recurrently across diverse plant lineages to enable survival in water-limited conditions. Many resurrection plants are polyploid, and several groups have hypothesized that polyploidy contributed to the evolution of desiccation tolerance. However, due to the vast phylogenetic distance between resurrection plant lineages, the rarity of desiccation tolerance, and the prevalence of polyploidy in plants, this hypothesis has been difficult to test. Here, we surveyed natural variation in morphological, reproductive, and desiccation tolerance traits across several cytotypes of a single species to test for links between polyploidy and increased resilience. We sampled multiple natural populations of the resurrection grass Microchloa caffra across an environmental gradient ranging from mesic to xeric in South Africa. We describe two distinct ecotypes of M. caffra that occupy different extremes of the environmental gradient and exhibit consistent differences in ploidy, morphological, reproductive, and desiccation tolerance traits in both field and common growth conditions. Interestingly, plants with more polyploid genomes exhibited consistently higher recovery from desiccation, were less reproductive, and were larger than plants with smaller genomes and lower ploidy. These data indicate that selective pressures in increasingly xeric sites may play a role in maintaining and increasing desiccation tolerance and are mediated by changes in ploidy.

Resurrection Plants-A Valuable Source of Natural Bioactive Compounds: From Word-of-Mouth to Scientifically Proven Sustainable Use.

Resurrection plant species are a group of higher plants whose vegetative tissues are able to withstand long periods of almost full desiccation and recover quickly upon rewatering. Apart from being a model system for studying desiccation tolerance, resurrection plant species appear to be a valuable source of metabolites, with various areas of application. A significant number of papers have been published in recent years with respect to the extraction and application of bioactive compounds from higher resurrection plant species in various test systems. Promising results have been obtained with respect to antioxidative and antiaging effects in various test systems, particularly regarding valuable anticancer effects in human cell lines. Here, we review the latest advances in the field and propose potential mechanisms of action of myconoside-a predominant secondary compound in the European members of the Gesneriaceae family. In addition, we shed light on the possibilities for the sustainable use of natural products derived from resurrection plants.

Dynamics of chromatin accessibility and genome wide control of desiccation tolerance in the resurrection plant Haberlea rhodopensis.

BACKGROUND: Drought is one of the main consequences of global climate change and this problem is expected to intensify in the future. Resurrection plants evolved the ability to withstand the negative impact of long periods of almost complete desiccation and to recover at rewatering. In this respect, many physiological, transcriptomic, proteomic and genomic investigations have been performed in recent years, however, few epigenetic control studies have been performed on these valuable desiccation-tolerant plants so far. RESULTS: In the present study, for the first time for resurrection plants we provide evidences about the differential chromatin accessibility of Haberlea rhodopensis during desiccation stress by ATAC-seq (Assay for Transposase Accessible Chromatin with high-throughput sequencing). Based on gene similarity between species, we used the available genome of the closely related resurrection plant Dorcoceras hygrometricum to identify approximately nine hundred transposase hypersensitive sites (THSs) in H. rhodopensis. The majority of them corresponds to proximal and distal regulatory elements of different genes involved in photosynthesis, carbon metabolism, synthesis of secondary metabolites, cell signalling and transcriptional regulation, cell growth, cell wall, stomata conditioning, chaperons, oxidative stress, autophagy and others. Various types of binding motifs recognized by several families of transcription factors have been enriched from the THSs found in different stages of drought. Further, we used the previously published RNA-seq data from H. rhodopensis to evaluate the expression of transcription factors putatively interacting with the enriched motifs, and the potential correlation between the identified THS and the expression of their corresponding genes. CONCLUSIONS: These results provide a blueprint for investigating the epigenetic regulation of desiccation tolerance in resurrection plant H. rhodopensis and comparative genomics between resurrection and non-resurrection species with available genome information.

Sugars in ferns and lycophytes growing on rocky outcrops from southeastern brazilian coast / Açúcares em samambaias e licófitas crescendo sobre afloramento rochoso da costa sudeste brasileira

The extreme conditions in rocky outcrops allow the occurrence of desiccation tolerant species. One strategy of these plants to withstand water shortage is the accumulation of sugars. In this paper, we report sugar levels and profile of three ferns and one lycophyte naturally hydrated growing on rocky outcrops from Southeastern Brazil. Anemia species have higher sugar contents than Doryopteris collina and Selaginella sellowii. The analyzed species have different sugar profiles. The ferns have glucose, fructose and sucrose, and the lycophyte has glucose and trehalose.

Nas condições ambientais extremas dos afloramentos rochosos ocorrem espécies tolerantes à dessecação. Uma das estratégias dessas plantas para resistir à restrição hídrica é o acúmulo de açúcares. No presente estudo, avaliamos a concentração e o perfil de açúcares de três espécies de samambaias e uma licófita, naturalmente hidratadas crescendo sobre afloramentos rochosos no sudeste do Brasil. As espécies de Anemia possuem maior concentração de açúcares em relação a Doryopteris collina e Selaginella sellowii. As espécies analisadas mostraram perfis distintos de açúcares. As samambaias apresentam glicose, frutose e sacarose, enquanto a licófita glicose e trealose.