Germination of many cacti across the Americas is light-dependent, but less has been explored regarding biochemical and morphophysiological alterations during germination and initial growth under different light spectra. Red and blue wavelengths, for instance, are predominantly absorbed by photosynthetic pigments, regulating plant growth. This study aimed to characterize physiological, anatomical and biochemical features of the mandacaru cactus (Cereus jamacaru DC.), an overexploited cactus crop from the Brazilian Caatinga, during germination and initial growth under white, red, and blue lights. Germination was tested under the three light treatments; the emerged seedlings were then cultivated under the same conditions. Seedling height and diameter were registered at 45, 60, 75, and 90 days after sowing. Photosynthetic pigments and total soluble sugars were quantified over time; anatomical analyses of the cladodes were also performed. White and red lights promoted the highest germination percentages (98–97%), with a decrease in the blue light (56%). Seedling height increased under the red light (35–36 mm) compared to the other treatments. Blue light tended to promote greater contents of chlorophylls and carotenoids. Total soluble sugars were greater in the blue light until 60 days, but equal among treatments at 75 and 90 days. Calcium oxalate crystals and amyloplasts were observed at 45 days in all treatments. This study shows contrasting physiological responses between light quality treatments, mostly related to the higher energy dissipation required under the blue wavelength. Future research should investigate seedling biomass production and relative growth rates, including comparisons with other populations of the mandacaru cactus.
The deposition of incompatible pollen grains in the stigma can interfere with the performance of compatible pollen grains and compromise the reproductive success of the species in the community. Ipomoea asarifolia, a self-incompatible species, occurs in sympathy with I. brasiliana, sharing pollinators, but without hybrid formation. However, this condition favors the deposition of auto pollen and interspecific pollen in the stigma, which can compromise the reproductive success of the species in the community. Given this, we investigated the influence of incompatible intra- and interspecific pollen grains on their reproductive success of I. asarifolia, based on analyses of natural pollination and controlled experiments. Our hypothesis is that the presence of incompatible pollen grains in the stigma negatively interferes with the formation of fruits and seeds in I. asarifolia. Fruit yield was significantly higher in manual cross-pollination than in natural pollination and mixed pollination experiments of compatible (intraspecific: cross-pollinated pollen) and incompatible (intraspecific: self-pollen and interspecific: pollen of I. brasiliana) pollens. Seed yield was significantly higher in cross-pollination than between the two mixed pollination experiments. Seed production was not significantly different between cross-pollination and natural pollination, nor between natural pollination and mixed pollination experiments. However, fruit and seed production was higher in cross-pollination than in other situations. And experiments with incompatible amounts of pollens do not form fruits. Few fruits and seeds are formed in the presence of incompatible pollens (intra and interspecific), which may be interfering with reproductive success in I. asarifolia, especially in the long term. We reinforce the importance of the selection of reproductive displacement in the species to minimize the flow of incompatible pollens and their reproductive interferences.
The interaction between polyamine content and antioxidant activity in plants can confer resistance to environmental stress. In this study, polyamines and antioxidant activities in T2-generation transgenic plants overexpressing the MsSAMS (Miscanthus sinensis S-adenosylmethionine synthetase) gene were studied. First, the results of plant length, leaf length, leaf width, leaf number, stem diameter, and chlorophyll content in the T2-generation transgenic plants into which the MsSAMS gene was inserted showed that there were only slight differences in the agricultural phenotype, and no significant difference was observed. Result of the analyses of polyamine-based components: putrescine, spermidine, and spermine showed that there was no detectable amount of putrescine in the control group, whereas in the T6 line, it was 399.14 ± 15.46 μg/g FW. Spermidine level was 1497.16 ± 53.28 μg/g FW and 146.97 ± 12.58 μg/g FW in the T17 and T9 lines of transgenic plants, respectively. Furthermore, free radical scavenging activity was measured using DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2′-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid)] assays. T17 line showed the highest antioxidant activity (1974.85 ± 18.06 μg/mL) in DPPH assay, whereas T6 line showed the highest activity (7390.12 ± 67.39 μg/mL) in ABTS assay. Results of the analysis of the total phenol and flavonoid content of the transgenic plants revealed that the T6 line and T2 line showed the highest values, respectively (208.20 ± 3.36 mg GAE/g and 22.07 ± 0.49 mg QE/g, respectively). These results suggest that the MsSAMS gene plays a role in enhancing antioxidant activity by increasing polyamine content.
The sycamore lace bug Corythucha ciliata (say) is the most important pest attacked the London planetree Platanus acerifolia worldwide. We propose that plant cytochrome P450s (CYP450s) are important and play key roles in P. acerifolia and C. ciliata interactions. Therefore, the identification of transcriptionally active CYP450 genes is considered essential for revealing the mechanisms involved in their interactions. So far, the CYP450 genes of P. acerifolia have not yet been reported. In this study, we identified and characterized 96 CYP450 genes in P. acerifolia. These genes were categorized into 8 clans, 41 families, and 60 subfamilies. Notably, 48 genes demonstrated a strong negative selection when compared with the CYP450 genes of Arabidopsis thaliana. The results of post-feeding induction of P. acerifolia by C. ciliata revealed ten CYP450 genes, which exhibited significant up-regulation. Gene expression levels of several identified CYP450 genes were validated by quantitative RT- PCR. Further, a putative allene oxide synthase gene encoding the key enzyme involved in the jasmonic acid biosynthesis (PaCYP74A187) was cloned, homology modeled, and subjected to molecular docking analysis. We propose PaCYP74A187 as a key candidate CYP450 gene in P. acerifolia induced by C. ciliata damage, altogether our findings enhance comprehensive understanding of the mechanisms associated with insect-plant interactions that will undoubtedly offer new targets for controlling C. ciliata populations.
Black gram is one of the important legume crops cultivated in the world, particularly in India mainly for protein requirements. It is grown mostly as a fallow crop in rotation with cereals. However, under saline stress conditions, the growth of the plants is reduced, ultimately resulting in a reduction in yield. The present investigations were carried out to evaluate the extent of genetic divergence and character association in 48 black gram genotypes for eleven biometric characters. In addition, the saline-tolerant genotypes were assessed in vitro. The analysis of variance revealed significant differences present in all the genotypes and showed a considerable amount of saline tolerance in the genotypes. Genetic diversity analysis using microsatellite markers revealed that out of a total of 21 SSR markers, 13 were polymorphic which revealed 47 alleles in forty-eight black gram genotypes with an average of 3 alleles per locus. Cluster analysis revealed that among the 21 markers used, 13 were found to be polymorphic with a transferability rate of 83%. From the present study, three genotypes, namely AUB 9, AUB 14 and AUB 20, were identified as saline-tolerant and were also confirmed by biometric and molecular analysis.
Miconia Ruiz & Pav. (Melastomataceae) is the seventh largest genus of flowering plants, but despite the great diversity of species (ca. 1900), no genome size (GS) studies have been published on the group. Studies have shown that GS can strongly predict phenotypic characteristics such as guard cell length, stomatal density, and epidermal cell area. As more genome sizes become available, a more comprehensive understanding of the role that GS variation plays in cellular characteristics emerges. Here, for the first time, we estimate GS by flow cytometry in four Miconia species, Miconia australis (Cham.) R. Goldenb., Miconia hyemalis St. Hil. & Naud. ex Naud., Miconia sellowiana (DC.) Naudin, and Miconia nianga (DC.) R.Goldenb.). Subsequently, we carried out a comparative analysis of the relationship between GS and three phenotypic characteristics: guard cell length, stomatal density, and epidermal cell area. The estimated GS ranged from 0.56 to 1.2 pg, and this variation may be attributed to the distinct reproductive modes among the species analyzed. We found a strong positive correlation between GS and guard cell length (r2 = 0.92) and a low correlation in stomatal density and epidermal cell area (r2 = 0.07 and 0.06, respectively). In this pioneering study, we provide some conclusions or speculations, and point to new questions yet to be explored in Miconia.
Our aim was to test the hypothesis that root growth of ‘Mandarin’ lime—a drought tolerant citrus rootstock—under water deficit is associated with higher nitric oxide (NO) content in roots. As a reference, ‘Swingle’ citrumelo was compared with ‘Mandarin’ lime, two well-known citrus rootstocks. ‘Valencia’ sweet orange plants grafted on ‘Mandarin’ lime or ‘Swingle’ citrumelo were kept well-hydrated or grown under water withholding. After 14 days of water deficit, root morphology was evaluated, and leaf and root samples were collected for NO analysis. Under low water availability, ‘Mandarin’ lime exhibited higher root NO content and root growth than ‘Swingle’ citrumelo. Indeed, NO seems to modulate not only root biomass accumulation but also root morphology as higher NO was associated with large increase in root length and area. Such findings suggest that root NO content is a relevant marker for early screening of drought-tolerant citrus genotypes. As a novelty, we show that ‘Mandarin’ lime drought tolerance is significantly associated with root NO content.
Floral mimicry is a captivating phenomenon wherein flowers imitate traits of other plants to attract specific pollinators. The Caesalpinioideae legumes in general have relatively unspecialized flowers, which has allowed the development of disparate morphologies adapted to different groups of pollinators. This study describes the pollination of Moldenhawera nutans L.P. Queiroz, G.P. Lewis & Allkin, and explores its potential floral mimicry toward Malpighiaceae flowers. Our investigation revealed that M. nutans is pollinated by bees of the genera Centris and Xylocopa. It also presents compelling evidence supporting the hypothesis of floral mimicry, including striking similarities in floral display, shared oil-collecting pollinators, oil collection behavior in M. nutans despite the absence of oil production, and the reliance on exogenous pollen for reproduction. These findings suggest that species of Centris visit M. nutans flowers under the mistaken impression of oil availability, subsequently transitioning to pollen collection. We explored other potential cases of floral mimicry with Malpighiaceae in the Caesalpinioideae legumes by optimizing the Malpighiaceae-like floral display on a dated phylogeny of this subfamily. However, current information does not allow us to determine whether the similarities in floral morphology represent cases of floral mimicry, phylogenetic inertia, or simple convergence. Hypothesis tests are suggested that can guide the study of these fascinating evolutionary processes in the group.
Cyclic nucleotide-gated ion channels (CNGCs) genes play an important role to tolerate the abiotic stress tolerance in crop plants. The present study was designed to compare the molecular aspects of CNCG genes in Arabidopsis thaliana L. and Helianthus annuus L. using various computational tools. Through protein blast analysis, we identified nine CNGCs in H. annuus and subcellular locations indicated that these genes were unevenly distributed in various cellular components. The phylogenetic analysis of CNGCs genes was conducted among of A. thaliana, H. annuus, Gossypium hirsutum L., Brassica oleracea L. and Brassica rapa L. It was noted that in phylogenetic tree CNCG proteins of these crops were divided into four clads. Expression profiling of RNA-seq-data indicated that HanCNGC16 and HanCNGC15 play putative role under drought stress. The cis-regulatory analysis also identified several stress-responsive elements in HanCNGCs. The comparative genomics provided insights into the evolutionary history, duplication, divergence, gene gain and loss, species relationship, and structural diversity of CNGC in five species. These findings will not only provide widespread implications of CNGCs for their roles under drought stress in various crop species but also provided a reference study for the CNGC gene family in H. annuus.
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