AoB Plants最新文献

Wild barley (Hordeum vulgare subsp. spontaneum), the progenitor of cultivated barley, is an invaluable genetic resource for enhancing crop resilience, particularly in drought-prone regions. Its natural adaptation to water-limited environments makes it an ideal candidate for studying mechanisms of drought tolerance. This study aims to investigate the genetic basis of drought tolerance by examining the correlation between molecular markers and root traits across a diverse collection of wild barley genotypes. This study evaluated the relationship between molecular markers and root traits in 114 wild barley genotypes collected from the natural distributional range in western Iran. The genotypes were subjected to normal (90%-95% field capacity) and water-stress (50%-55% field capacity) conditions. Root, physiological and seedling traits were carefully measured, and the genotypes were analyzed using 35 molecular markers, including simple sequence repeats (SSRs) and expressed sequence tag-SSRs (EST-SSRs). Statistical association analyses were performed to assess the correlation between markers and root traits. The study revealed significant genetic diversity among the 114 wild barley genotypes, reflecting distinct environmental pressures in their regions of origin. Several molecular markers, especially BMAG0603 and GBM1126, consistently exhibited strong associations with desirable root traits, such as increased root length, root density, and seedling vigor under both normal and water-stressed conditions. These markers are valuable for marker-assisted selection (MAS) in breeding programs aimed at improving drought tolerance. Specific chromosomal regions critical for root trait development were identified, offering insights into the genetic control of drought tolerance in barley. The results highlight the importance of using molecular markers to enhance drought tolerance in barley. The identification of key markers associated with beneficial root traits offers a valuable resource for breeding programs focused on drought resilience. Further research should explore marker-trait associations under various stress conditions to optimize the genetic potential of wild barley for crop improvement strategies.

Drought stress can affect the growth of soybean seedlings because soybeans require a large amount of water for growth and development. However, the storage and redistribution of water in the soil are related to the soil's texture. This experiment used the soybean varieties hefeng46 and heinong84, and studied the effects of four moisture conditions on the content of membrane lipid peroxides, the activities of enzymes and non-enzymatic antioxidants the content, and also the key enzymes of carbon and nitrogen metabolism in soybean seedlings under loamy sand and sandy loam soil conditions. The results suggested that as the duration of drought increased, in loamy sand, under serious drought (SD), the contents of malondialdehyde and proline, as well as the activities of superoxide dismutase and glutamine synthetase, in hefeng46 and heinong84 were significantly increased by 160% and 146%, 1431% and 1924%, 167% and 282%, and 64% and 69%, respectively, compared to the normal water (CK). However, in sandy loam, the hydrolytic direction activity of sucrose synthase in intermediate drought treated hefeng46 and heinong84 was significantly increased by 1247% and 169% compared to the CK, and the content of reduced glutathione was dramatically raised. In contrast, the synthetic direction activity of sucrose synthase in SD treated hefeng46 and heinong84 was significantly decreased by 69% and 70% compared to the CK. The combined results indicated that under drought stress, soybean in sandy loam soil exhibited stronger drought resistance.

Panax japonicus is a valuable medicinal plant whose rhizomes are rich in diverse ginsenosides. However, its perennial growth habit can significantly influence the quality and consistency of the herbal product. Despite its medicinal importance, the molecular regulatory mechanisms underlying saponin biosynthesis during different growth stages remain largely unknown. In this study, we conducted a comprehensive analysis of saponin content and transcriptomic profiles in P. japonicus rhizomes from plants aged 2-5 years. High-performance liquid chromatography revealed significant variations in saponin levels across different growth stages. Specifically, the concentrations of the major saponins, Ginsenoside Ro and Chikusetsusaponin IVa, decreased with increasing plant age, while the minor components, Zingibroside R1 and Calenduloside E, showed an upward trend. Transcriptome sequencing generated 78.53 Gb of clean reads and assembled 90 912 unigenes, of which 61 268 unigenes were successfully annotated. Comparative analysis indicated that P. japonicus shares the highest sequence homology with Daucus carota subsp. sativa. In addition, 37 enzymes involved in the triterpenoid saponin biosynthesis pathway were identified through differential gene expression analysis. Weighted Gene Co-expression Network Analysis further identified seven gene modules significantly associated with triterpenoid saponin content. Notably, genes encoding Cytochrome P450s and Uridine diphosphate-glycosyltransferases, which are key enzymes in saponin biosynthesis, were highlighted for further investigation. This study fills a critical knowledge gap in the genetic regulation of saponin biosynthesis in P. japonicus throughout its developmental stages and provides novel insights into the molecular mechanisms regulating ginsenoside accumulation. These findings offer a valuable foundation for future genetic improvement and quality control of P. japonicus as a traditional medicinal herb.

Plant responses to the presence of neighbours and social interactions between them have the potential to alter fundamental aspects of plants' evolution, persistence, and coexistence. The present study employs a novel approach to investigate the three-dimensional movement of root tips in response to a neighbouring plant of the same or different species. We collected data from maize and pea plants in three experimental conditions: (i) individual condition, in which plants grew without neighbours; (ii) social growing condition with a conspecific neighbour, in which plants grew in the presence of another plant of the same species; and (iii) social growing with a heterospecific neighbour, in which plants grew in the presence of another plant of a different species. The results indicate that roots display a more pronounced 'exploratory' behaviour when growing under social conditions. For both maize and pea plants, a higher incidence of aggregative behaviour (primary root moving towards the neighbour) was observed when plants grew near a conspecific when compared with an heterospecific neighbour. According to our analyses, roots showing aggregative behaviour seem to detect the neighbouring root with a good level of geometrical precision as shown by the observed directional movement. We contend that this study provides for the first time quantitative information on the modulation of kinematic and oscillatory features of root movements, which are vital for a deeper understanding of plants' below-ground interactions.

The evolution of heterotrophic lifestyle entails varying degrees of plastome degradation. Yet, the evolutionary trajectory of plastome degradation associated with parasitism remains poorly explored in hemiparasites. We sequenced, assembled, and annotated the complete plastomes of five species of Psittacanthus mistletoes. In addition, publicly available plastomes of 58 species in Loranthaceae were obtained and re-annotated for phylogenetic and comparative analyses. We used a comparative phylogenetic approach to evaluate whether patterns of pseudogenization and gene loss differ among lineages of hemiparasites in Loranthaceae. Gene order was highly conserved, with higher sequence similarity and structural conservation between closely related Psittacanthus species but with considerable plastome size variation (from 121 238 to 125 427 bp). The expansion and contraction at the borders of inverted repeats (IRs) and intergenic regions variation greatly contribute to size variations among Psittacanthus plastomes. Phylogenetic analysis of plastomes of 60 species in Loranthaceae including 5 Psittacanthus species of the previously unsampled tribe Psittacantheae was largely congruent with previous phylogenetic studies. The loss of most of the ndh complex (10 out of 11 genes), rpl32, rps15, and rps16 genes, was identified in all studied Psittacanthus species. Also, the loss and pseudogenization of rpl33 and rpl36 genes in Psittacanthus were uncommon in other Loranthaceae species. The structural variation uncovered in Psittacanthus plastomes reveals that, despite high synteny, significant size variation exists among species. This variation can be attributed to processes such as variations in the length of intergenic regions and the expansion/contraction of IR borders, traits that have been comparatively understudied in earlier Loranthaceae works.

Epiphytes occupy arboreal niches in forest ecosystems, which are particularly vulnerable to drought stress due to the absence of a buffered substrate for water retention in epiphytic habitats. Characterizing the differences and relationships among plant morphological and physiological traits is critical for elucidating different adaptive strategies. However, it is still unclear whether there are differences in floral and leaf morphological and physiological traits between epiphytic and terrestrial plants, and whether there is a correlation between flower and leaf traits in epiphytes. Here, we measured 13 floral traits and 8 leaf traits from 7 terrestrial and 12 epiphytic Cymbidium species. We found that, compared with these terrestrial Cymbidium species, epiphytic species had a higher leaf mass per unit area, greater leaf thickness, a longer time required to dry saturated leaves to 70% relative water content, and greater epidermal thickness. However, no significant differences in floral traits were found between the epiphytic and the terrestrial species, which suggest that the water-related traits of flowers in Cymbidium are not influenced by the plant's life forms. Moreover, there were no strong associations between floral and leaf morphological and physiological traits floral traits, implying that they may be developmentally modular. These findings provide novel insights into the decoupled evolution of vegetative and reproductive traits in response to environmental pressures. By shedding light on this pattern, our study advances the understanding of plant adaptation strategies in heterogeneous habitats within the genus Cymbidium, providing a more comprehensive view of how plants evolve to flourish in diverse ecological conditions.

Agroforestry is a major adaptation and mitigation strategy facing climate warming, but its agronomic viability depends on actual plant responses to shade conditions. Growing fruit trees under dominant trees may reduce the risks related to extreme climatic events, such as frost or heat waves. Nonetheless, except for some sciaphilous plants, such as coffee or cacao, their physiological and architectural responses to agroforestry conditions are little known, especially in temperate climate. We present a dataset describing the architecture and morphology of 45 young apple trees, acquired in two consecutive years, along a radiative gradient, as in three growing conditions of an agroforestry plot: (i) the open field, (ii) between, and (iii) along rows of dominant walnut trees. The data are stored as standard multi-scale tree graphs that allow to store the topology, geometry, and attributes of the plant at different scales. It includes plant traits at three topological scales: whole tree, growth unit, and the internode. The traits include organ fate (latent, vegetative, floral bud, and bud extinction sites); length and an estimate of the leaf area of growth units; diameter, zenith, and azimuth angles of second-order branches. The number of leaves, flowers, fruits, and fruit drops is also counted on a sample of 10, possibly apical, flower buds per tree. The dataset includes ancillary measurements on sampled shoots, used to derive allometric relationships between shoot length and leaf area; and an estimate of the radiation reaching each apple tree during the vegetative season. The multi-scale description and the different light growing conditions characterizing the digitized trees allow to investigate relationships between the shade-related agroforestry environment and the apple tree morphological and architectural plasticity, during the early tree development, from the internode to the whole tree.

Increasing frequency and intensity of global warming pose a profound threat to plant species persistence. Most investigations on plants' resilience to heat events focus on few genotypes of model species. Novel insights into resilience mechanisms will be gained by focusing on natural variation in thermotolerance and its relationship to local-abiotic factors. Additionally, studying species that survived 'ancient periods' of high temperatures provides insight into resilience mechanisms. Within a species, we assessed spatial thermotolerance variation, its association with temperature and light, while testing for thermotolerance sex differences and its relationship with population sex ratios. We used Marchantia inflexa, a species with unisexual individuals exhibiting spatial variation in physiologies and life histories. To assess field basal thermotolerance (field BT), we examined the efficiency of photosystem II recovery following a heat treatment (53°C for 45 min) in over 200 field-collected plants from seven sites. We further examined whether field BT is linked to initial physiological traits or environmental factors and assessed its potential as a predictor of sex ratios. Following the heat treatment, plants exhibited damage and were still recovering by day ten; recovery was generally higher in road- relative to stream-collected plants with notable variation among sites. Thermotolerance was positively associated with light and tended to be negatively associated with temperature. This light-thermotolerance relationship was more pronounced in males, and thermotolerance differences between females and males tended to be positively related to the proportion of females. The positive light-thermotolerance association suggests that light is a key factor driving heat stress resilience in M. inflexa. The light-thermotolerance relationship for males vs. females implies sex-specific strategies for coping with abiotic stress. There were subtle thermotolerance impacts on population sex ratios. These insights broaden the understanding of the thermotolerance diversity present within a species.

Plants have long-lasting and complex interactions with herbivores, including insects and mammals. In response to high herbivory rates, plants either tolerate biomass loss or develop several defence mechanisms, such as physical defence. The resource availability hypothesis (RAH) predicts that plant defence investment is dependent on resource availability and plant's life history. However, the effect of resource availability on plant investment in defence is mediated through biotic pressure. We tested the effects of soil qualities and browsing pressure on the physical defence and reproductive investments in Acacia sieberiana at the Pendjari Biosphere Reserve in West Africa. We selected six populations, including three in the Pendjari River floodplain where soil moisture is high but with high elephant browsing pressure, and three populations on the plateau in the hunting zone where soils are drier and relatively poorer with a lower density of elephants. We found greater investment in physical defence for trees in the floodplain. Furthermore, A. sieberiana trees produced less fruit in the floodplain than in the plateau. Contrary to the predictions of the RAH, we found more and longer thorns in populations in the richer floodplains than on the plateau. This was linked to higher elephant browsing pressure in the floodplains. This physical defence was probably induced to cope with the episodic but high levels of herbivory observed in this environment. Surprisingly, the negative influence of thorn number and size on the likelihood of elephant damage was observed only in the rich floodplains and not in plateau sites. Altogether, our study demonstrates that the influence of resource availability (soil moisture, pH, and fertility) in shaping plant physical defence can be outweighed by high herbivory pressure.

The genus Larrea has an amphitropical distribution in North and South American deserts, and its phylogeny remains unresolved. This genus is conspicuous and specious within the Monte Desert, the largest, although understudied, southern South American dryland. Larrea presents an interesting case for phylogenetic studies due to its paternally inherited chloroplasts, its species hybridize in nature, and although nominal species are morphologically distinct, hybrids might be cryptic. We analysed ITS2 nuclear (nDNA) and rbcL chloroplast (cpDNA) sequences of the bifoliolate section, Bifolium, including L. tridentata (Lt) from North America, and its South American congeners: L. cuneifolia (Lc) and L. divaricata (Ld), and sequences of the multifoliolate Larrea section: L. ameghinoi (La), L. nitida (Ln), and a morphological hybrid swarm. We aligned and analysed sequences from 111 individuals collected at 31 populations sampled along the range of each species. The nDNA revealed 56 haplotypes, and median-joining and maximum likelihood reconstructions provided clear separation among species and suggested hybridization between Lc-Ld. The nuclear phylogeny showed that the section Larrea diverged earlier than Bifolium, within which Lc diverged first, meanwhile, consistent with previous studies, Lt forms a monophyletic group sister to Ld. Comparatively, cpDNA was less variable, with only six haplotypes shared between Ln-Lc and Ln-La, and rarely between Ld-Lc. Our results emphasize the significance of separately considering nuclear and plastid evolutionary signals when reconstructing unresolved relationships. While nuclear markers clarified phylogenetic relationships and cryptic hybridization among Larrea species, the chloroplast revealed the retention of widespread ancient polymorphisms, which were conserved in populations of distinct species. Each marker provided insights into particular evolutionary patterns, highlighting that genetic variation may be more influenced by hybridization and mode of chloroplast inheritance than previously recognized.