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With the advent of genomic and other omics technologies, the last decades have witnessed a series of steady and important breakthroughs in the understanding of genetic determinants of different reproductive systems in vascular plants and especially on how sexual reproduction shaped their evolution. In contrast, the molecular mechanisms of these fundamental aspects of the biology of bryophytes, a group of non-vascular embryophyte plants sister to all tracheophytes, are still largely obscure. The recent characterization of the sex chromosomes and genetic switches determining sex in bryophytes and emerging approaches for molecular sexing of gametophytes hold great promise for elucidation of the evolutionary history as well as the conservation of this species-rich but understudied group of land plants. [ABSTRACT FROM AUTHOR]

Physcomitrium eurystomum Sendtn. is a very rare European ephemeral funaroid moss. The entire European population of this species is considered threatened and it is red-listed in many regions and countries. In addition to being recognized as threatened and included in nature conservation legislation, it also requires active protection measures. This study aims to contribute to effective conservation practices for P. eurystomum. Different conservation physiology tests were carried out to propagate this species to achieve a reliable procedure for biomass production and the potential reintroduction of germplasm. Ex situ tests, both in vitro and ex vitro , were carried out to determine the optimal method for spore production under laboratory conditions, considering that the spores are the best propagules for the reintroduction of the species. An important outcome of this research is a deeper understanding of the role of the spore bank of this species for its survival in a variable environment. Some additional characterizations of the biology of this ephemeral moss species are also discussed, such as the functioning of the photosynthetic apparatus of the vegetative vs. sexual phases to clarify the transition to the reproductive phase. It is proposed that both types of sporophytes be used in conservation practices due to viable spore bank self-sustainability in rapidly changing environmental conditions. [ABSTRACT FROM AUTHOR]

Plantago (plantains, Plantaginaceae) is a cosmopolitan genus including over 250 species used as functional foods, forage, and traditional medicine. Among them, Plantago lanceolata is commonly used as an ingredient of herbal products, but the close similarity to other Plantago species can cause misidentifications with potentially serious consequences for product safety/quality. To test the possibility of developing species-specific barcoding markers, we de novo assembled plastome sequences of individuals of Plantago argentea, Plantago atrata, P. lanceolata, and Plantago maritima. These genomes were characterized in comparison with both previously sequenced conspecific accessions and other publicly available plastomes, thus providing an assessment of both intraspecific and interspecific genetic variation in Plantago plastomes. Additionally, molecular evolutionary analyses indicated that eleven protein-coding genes involved in different plastid functions in Plantago plastomes underwent positive selection, suggesting they might have contributed to enhancing species' adaptation during the evolutionary history of Plantago. While the most variable mutational hotspots in Plantago plastomes were not suitable for the development of species-specific molecular markers, species-specific polymorphisms could discriminate P. lanceolata from its closest relatives. Taken together, these results highlight the potential of plastome sequencing for the development of molecular markers to improve the identification of species with relevance in herbal products. [ABSTRACT FROM AUTHOR]

Thiol-peptides, such as glutathione and phytochelatins, are believed to play a crucial role in regulating metal micronutrient needs (in particular, copper, iron, and zinc), and in detoxifying their excessive amounts. This study provides insight into the mechanisms involved in detoxification, starvation, and physiological control of the aforesaid metals in the liverwort Marchantia polymorpha. The results show that the phytochelatin synthase activity in gametophytes of M. polymorpha is induced mainly by zinc, followed by copper, and iron. Interestingly, the amount of phytochelatins produced seems to be controlled by the enzyme activity, rather than by the expression level of its gene. Moreover, when gametophytes are deprived of zinc, copper, and iron, phytochelatin levels decrease, compared with normal nutrient supply. Phytochelatins and glutathione, on the other hand, appear to play a key role in detoxification of excess zinc, copper, and iron, particularly when these thiol-peptides are released extracellularly. This suggests a potential novel function for phytochelatins and glutathione as detoxifying compounds also in the extracellular environment. [ABSTRACT FROM AUTHOR]

Stomata control CO2 uptake for photosynthesis and water loss through transpiration, thus playing a key role in leaf thermoregulation, water-use efficiency (iWUE), and plant productivity. In this work, we investigated the relationship between several leaf traits and hypothesized that stomatal behavior to fast (i.e. minutes) environmental changes co-determines, along with steady-state traits, the physiological response of grapevine to the surrounding fluctuating environment over the growing season. No relationship between iWUE, heat stress tolerance, and stomatal traits was observed in field-grown grapevine, suggesting that other physiological mechanisms are involved in determining leaf evaporative cooling capacity and the seasonal ratio of CO2 uptake (A) to stomatal conductance (g s). Indeed, cultivars that in the field had an unexpected combination of high iWUE but low sensitivity to thermal stress displayed a quick stomatal closure to light, but a sluggish closure to increased vapor pressure deficit (VPD) levels. This strategy, aiming both at conserving water under a high to low light transition and in prioritizing evaporative cooling under a low to high VPD transition, was mainly observed in the cultivars Regina and Syrah. Moreover, cultivars with different known responses to soil moisture deficit or high air VPD (isohydric versus anisohydric) had opposite behavior under fluctuating environments, with the isohydric cultivar showing slow stomatal closure to reduced light intensity but quick temporal responses to VPD manipulation. We propose that stomatal behavior to fast environmental fluctuations can play a critical role in leaf thermoregulation and water conservation under natural field conditions in grapevine. [ABSTRACT FROM AUTHOR]

Epidermal Patterning Factor Like 9 (EPFL9), also known as STOMAGEN, is a cysteine-rich peptide that induces stomata formation in vascular plants, acting antagonistically to other epidermal patterning factors (EPF1, EPF2). In grapevine there are two EPFL9 genes, EPFL9-1 and EPFL9-2 sharing 82% identity at protein level in the mature functional C-terminal domain. In this study, CRISPR/Cas9 system was applied to functionally characterize VvEPFL9-1 in ‘Sugraone’, a highly transformable genotype. A set of plants, regenerated after gene transfer in embryogenic calli via Agrobacterium tumefaciens, were selected for evaluation. For many lines, the editing profile in the target site displayed a range of mutations mainly causing frameshift in the coding sequence or affecting the second cysteine residue. The analysis of stomata density revealed that in edited plants the number of stomata was significantly reduced compared to control, demonstrating for the first time the role of EPFL9 in a perennial fruit crop. Three edited lines were then assessed for growth, photosynthesis, stomatal conductance, and water use efficiency in experiments carried out at different environmental conditions. Intrinsic water-use efficiency was improved in edited lines compared to control, indicating possible advantages in reducing stomatal density under future environmental drier scenarios. Our results show the potential of manipulating stomatal density for optimizing grapevine adaptation under changing climate conditions. [ABSTRACT FROM AUTHOR]