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<jats:p>Cys-tathionine-β-synthase (CBS) domain-containing proteins (CDCPs) are essential for regulating plant responses to various biotic and abiotic stressors. This study describes the systematic identification and characterization of CDCP family genes in <jats:italic>Saccharum spontaneum</jats:italic>. A total of 95 <jats:italic>SsCDCP</jats:italic> genes and eight phylogenetic groups were identified that were distributed over 29 chromosomes of the AP85-441 genome. Most (78/95) <jats:italic>SsCDCPs</jats:italic> underwent fragment duplication events, and 64 gene pairs were located in synteny blocks. Expression profiling of nine <jats:italic>ShCDCP</jats:italic>s was also carried out in the <jats:italic>Saccharum</jats:italic> spp. cultivars ROC22 and MT11-611 that are resistant and susceptible to red stripe, respectively, in response to: (i) Infection by the bacterial pathogen <jats:italic>Acidovorax avenue</jats:italic> subsp. <jats:italic>avenae</jats:italic> (<jats:italic>Aaa</jats:italic>); (ii) abiotic stressors (drought and salinity); and (iii) exogenous salicylic acid (SA) treatment. Members of one gene pair (<jats:italic>ShCBSD-PB1-5A</jats:italic> and <jats:italic>ShCBSD-PB1-7A-1</jats:italic>) with a fragment duplication event acted as negative regulators in sugarcane under four stresses, as supported by the significantly decreased expression levels of <jats:italic>ShCBSD-PB1-5A</jats:italic> (23–83%) and <jats:italic>ShCBSD-PB1-7A-1</jats:italic> (15–75%) at all-time points, suggesting that they have functional redundancy. Genes in another pair, <jats:italic>ShCBS-4C</jats:italic> and <jats:italic>ShCBS-4D-1</jats:italic>, which have a fragment duplication event, play opposing regulatory roles in sugarcane exposed to multiple stresses, particularly <jats:italic>Aaa</jats:italic> and NaCl treatments. <jats:italic>ShCBS-4C</jats:italic> expression was significantly decreased by 32–77%, but <jats:italic>ShCBS-4D-1</jats:italic> expression was dramatically upregulated by 1.2–6.2-fold in response to <jats:italic>Aaa</jats:italic> treatment of both cultivars across all-time points. This result suggested that both genes exhibited functional divergence. Meanwhile, the expression of <jats:italic>SsCBSDCBS-5A</jats:italic> was significantly upregulated in ROC22 by 1.4–4.6-fold in response to the four stressors. These findings provide important clues for further elucidating the function of <jats:italic>ShCDCP</jats:italic> genes in sugarcane responding to a diverse range of stresses.</jats:p>

<jats:p>Soil contamination with toxic heavy metals [such as lead (Pb)] is becoming a serious global problem due to the rapid development of the social economy. However, accumulation of Pb in plant parts is very toxic for plant growth and decreases crop yield and productivity. In the present study, we have investigated the different concentrations of Pb in the soil i.e., [0 (no Pb), 50, and 100 mg kg<jats:sup>–1</jats:sup>] to study plant growth and biomass, photosynthetic pigments and gas exchange characteristics, oxidative stress indicators and the response of various antioxidants (enzymatic and non-enzymatic), nutritional status of the plant, organic acid exudation pattern and also Pb accumulation in the roots and shoots of the plants of two varieties of tomato (<jats:italic>Solanum lycopersicum</jats:italic> L.) i.e., Roma and Cchuas, grown under different levels of synergic acid [no spray (NS), water spray (WS), 0.3-0.5°μM]. Results from the present study showed that the increasing levels of Pb in the soil decreased non-significantly (<jats:italic>P</jats:italic> &amp;lt; 0.05) shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content, net photosynthesis, stomatal conductance, transpiration rate, soluble sugar, reducing sugar, non-reducing sugar contents, calcium (Ca<jats:sup>2+</jats:sup>), magnesium (Mg<jats:sup>2+</jats:sup>), iron (Fe<jats:sup>2+</jats:sup>), and phosphorus (P) contents in the roots and shoots of the plants. However, Pb toxicity also induced oxidative stress in the roots and shoots of the plants by increasing malondialdehyde (MDA), hydrogen peroxide (H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>), and electrolyte leakage (EL) which also induced increased the compounds of various enzymatic and non-enzymatic antioxidants and also organic acids exudation pattern in the roots such as fumaric acid, acetic acid, citric acid, formic acid, malic acid, oxalic acid contents and increased the concentration of Pb in different parts of the plants. Results also show that the Cchuas showed better growth and development compared to Roma, under the same levels of Pb in the soil. The alleviation of Pb toxicity was induced by the application of synergic acid, and results showed that the application of synergic acid increased plant growth and biomass and also increased the gas exchange characteristics and antioxidant capacity in the roots and shoots of the plants. Research findings, therefore, suggested that synergic acid application can ameliorate Pb toxicity in <jats:italic>S. lycopersicum</jats:italic> varieties and result in improved plant growth and composition under metal stress as depicted by balanced exudation of organic acids.</jats:p>

<jats:p>The study was undertaken to characterize the total phenolics, flavonoids, essential oils, quinones, tannins and antioxidant activity of 15 samples of wild <jats:italic>Murraya koenigii</jats:italic> (L.) Spreng. (MK) leaves obtained from different locations of Himachal Pradesh at various growth stages. The results indicated a significant variation in total phenolic content which ranged from [(170.09 ± 4.59 to 303.57 ± 7.94) in pre-flowering, (266.48 ± 7.49 to 450.01 ± 11.78) in the flowering stage, and (212.72 ± 5.37 to 363.85 ± 9.79) in fruiting stage], expressed as mg tannic acid equivalents (TAE)/g. The total flavonoid content ranged from [(15.17 ± 0.36 to 33.40 ± 0.81) in pre-flowering, (25.16 ± 0.67 to 58.17 ± 1.52) in flowering stage, and (17.54 ± 0.42 to 37.34 ± 0.97) in fruiting stage], expressed as mg catechin equivalent (CE)/g. Total tannin content ranged from [(75.75 ± 1.69 to 143 ± 3.74) in pre-flowering, (116 ± 3.26 to 207 ± 5.42) in the flowering stage, and (47 ± 1.18 to 156 ± 4.05) in fruiting stage], expressed as mg TAE/g. The essential oil content ranged from (0.64 ± 0.01 to 0.89 ± 0.02%) in pre-flowering, (0.85 ± 0.02 to 1 ± 0.02%) in flowering stage, and (0.54 ± 0.01 to 0.7 ± 0.01%) in fruiting stage. Quinones ranged from [(2.05 ± 0.05 to 2.97 ± 0.07) in pre-flowering, (3.07 ± 0.07 to 4.95 ± 0.13) in flowering stage, and (1.02 ± 0.02 to 1.96 ± 0.04) in fruiting stage], expressed as mM/min/g tissue. Antioxidant activity ranged from [(4.01 ± 0.09 to 7.42 ± 0.17) in pre-flowering, (8.08 ± 0.19 to 13.60 ± 0.35) in flowering stage, and (3.11 ± 0.06 to 6.37 ± 0.15) in fruiting stage], expressed as μg/ml. Data was subjected to multivariate analysis using principal component analysis (PCA), hierarchical clustering analysis (HCA). This was used for elucidating the intricate relationships between the phytochemical properties. All evaluated phytochemical parameters significantly increased during the growth transition from pre-flowering to the flowering stage, followed by their gradual decrease during the fruiting stage. The present study can serve as rationale for commercializing MK for aromatic and phytopharmaceutical industries.</jats:p>

<jats:p>Tartary buckwheat (TB) is a pseudocereal rich in flavonoids, mainly including flavonols and anthocyanins. The flavonoid 3′-hydroxylase (F3′H) is a key enzyme in flavonoid biosynthesis and is encoded by two copies in TB genome. However, its biological function and effects on flavonol and anthocyanin synthesis in TB have not been well validated yet. In this study, we cloned the full-length <jats:italic>FtF3′H1</jats:italic> gene highly expressed in all tissues (compared with <jats:italic>FtF3′H2</jats:italic>) according to TB flowering transcriptome data. The corresponding FtF3′H1 protein contains 534 amino acids with the molecular properties of the typical plant F3′H and belongs to the CYP75B family. During the flowering stage, the <jats:italic>FtF3′H1</jats:italic> expression was highest in flowers, and its expression pattern showed a significant and positive correlation with the total flavonoids (<jats:italic>R</jats:italic><jats:sup>2</jats:sup> &amp;gt; 0.95). The overexpression of <jats:italic>FtF3′H1</jats:italic> in <jats:italic>Arabidopsis thaliana</jats:italic>, <jats:italic>Nicotiana tabacum</jats:italic> and TB hairy roots resulted in a significant increase in anthocyanin contents (<jats:italic>p</jats:italic> &amp;lt; 0.05) but a decrease in rutin (<jats:italic>p</jats:italic> &amp;lt; 0.05). The average anthocyanin contents were 2.94 mg/g (fresh weight, FW) in <jats:italic>A. thaliana</jats:italic> (about 135% increase), 1.18 mg/g (FW) in <jats:italic>tobacco</jats:italic> (about 17% increase), and 1.56 mg/g (FW) TB hairy roots (about 44% increase), and the rutin contents were dropped to about 53.85, 14.99, 46.31%, respectively. However, the expression of genes involved in anthocyanin (DFRs and ANSs) and flavonol (FLSs) synthesis pathways were significantly upregulated (<jats:italic>p</jats:italic> &amp;lt; 0.05). In particular, the expression level of <jats:italic>DFR</jats:italic>, a key enzyme that enters the anthocyanin branch, was upregulated thousand-fold in <jats:italic>A. thaliana</jats:italic> and in <jats:italic>N. tabacum</jats:italic>. These results might be attributed to <jats:italic>FtF3′H1</jats:italic> protein with a higher substrate preference for anthocyanin synthesis substrates. Altogether, we identified the basic biochemical activity of FtF3′H1 <jats:italic>in vivo</jats:italic> and investigated its involvement in anthocyanin and flavonol metabolism in plant.</jats:p>

<jats:p>Litchi flowering management is an important link in litchi orchard management. Statistical litchi flowering rate data can provide an important reference for regulating the number of litchi flowers and directly determining the quality and yield of litchi fruit. At present, the statistical work regarding litchi flowering rates requires considerable labour costs. Therefore, this study aims at the statistical litchi flowering rate task, and a combination of unmanned aerial vehicle (UAV) images and computer vision technology is proposed to count the numbers of litchi flower clusters and flushes in a complex natural environment to improve the efficiency of litchi flowering rate estimation. First, RGB images of litchi canopies at the flowering stage are collected by a UAV. After performing image preprocessing, a dataset is established, and two types of objects in the images, namely, flower clusters and flushes, are manually labelled. Second, by comparing the pretraining and testing results obtained when setting different training parameters for the YOLOv4 model, the optimal parameter combination is determined. The YOLOv4 model trained with the optimal combination of parameters tests best on the test set, at which time the mean average precision (mAP) is 87.87%. The detection time required for a single image is 0.043 s. Finally, aiming at the two kinds of targets (flower clusters and flushes) on 8 litchi trees in a real orchard, a model for estimating the numbers of flower clusters and flushes on a single litchi tree is constructed by matching the identified number of targets with the actual number of targets <jats:italic>via</jats:italic> equation fitting. Then, the data obtained from the manual counting process and the estimation model for the other five litchi trees in the real orchard are statistically analysed. The average error rate for the number of flower clusters is 4.20%, the average error rate for the number of flushes is 2.85%, and the average error for the flowering rate is 1.135%. The experimental results show that the proposed method is effective for estimating the litchi flowering rate and can provide guidance regarding the management of the flowering periods of litchi orchards.</jats:p>

<jats:p>Understanding the evolutionary and ecological processes driving population differentiation and speciation can provide critical insights into the formation of biodiversity. Here, we examine the link between population genetic processes and biogeographic history underlying the generation of diversity in the Hengduan Mountains (HM), a region harboring a rich and dynamic flora. We used restriction site-associated DNA sequencing to generate 1,907 single-nucleotide polymorphisms (SNPs) and four-kb of plastid sequence in species of the <jats:italic>Gentiana hexaphylla</jats:italic> complex (Gentianaceae). We performed genetic clustering with spatial and non-spatial models, phylogenetic reconstructions, and ancestral range estimation, with the aim of addressing the processes influencing diversification of <jats:italic>G. hexaphylla</jats:italic> in the HM. We find the <jats:italic>G. hexaphylla</jats:italic> complex is characterized by geographic genetic structure with clusters corresponding to the South, North and the central HM. Phylogenetic reconstruction and pairwise <jats:italic>F</jats:italic><jats:sub>ST</jats:sub> analyses showed deep differentiation between Southern and Northern populations in the HM. The population in Mount Taibai exhibited the highest genetic similarity to the North HM. Ancestral range estimation indicated that the <jats:italic>G. hexaphylla</jats:italic> complex originated in the central HM and then diverged in the Pliocene and the Early Pleistocene, before dispersing widely, resulting in the current distinct lineages. Overall, we found deep genomic differentiation in the <jats:italic>G. hexaphylla</jats:italic> complex corresponds to geographic barriers to dispersal in the HM and highlights a critical role of the uplift of the Daxue Mountains and subsequent climatic fluctuations underlying diversification. The colonization of <jats:italic>G. hexaphylla</jats:italic> in the Mount Taibai region suggests directional dispersal between the alpine flora of the Qinling Mountains and the HM.</jats:p>

<jats:p>High temperature negatively affects reproductive process significantly, leading to tremendous losses in crop quality and yield. Zhinengcong (ZNC), a crude extract from the endophytic fungus <jats:italic>Paecilomyces variotii</jats:italic>, has been shown to improve plant growth and resistance to biotic and abiotic stresses. We show here that ZNC can also alleviate heat stress-induced reproductive defects in <jats:italic>Solanum lycopersicum</jats:italic>, such as short-term heat-induced inhibition on pollen viability, germination and tube growth, and long-term heat stress-induced pollen developmental defects. We further demonstrated that ZNC alleviates heat stress by downregulating the expressions of ROS production-related genes, RBOHs, and upregulating antioxidant related genes and the activities of the corresponding enzymes, thus preventing the over accumulation of heat-induced reactive oxygen species (ROS) in anther, pollen grain and pollen tube. Furthermore, spraying application of ZNC onto tomato plants under long-term heat stress promotes fruit and seed bearing in the field. In summary, plant endophytic fungus extract ZNC promotes the reproductive process and yield of tomato plants under heat stress and presents excellent potential in agricultural applications.</jats:p>

<jats:p><jats:italic>Toona ciliata</jats:italic> is a traditional woody plant that can be used as a medicinal material in China. The extracts of its roots, stems, leaves, and flowers all have a wide range of bioactive compounds. However, <jats:italic>T. ciliata</jats:italic> has been facing an unresolved pest problem caused by <jats:italic>Hypsipyla robusta</jats:italic> Moore (HRM), which seriously affects its growth and development. In this study, the expression level of <jats:italic>TcMYB3</jats:italic> gene reached the maximum (28-fold) at 12 h and transcriptome sequencing of young stems eaten by HRM for 0, 3, 12, and 21 h were performed. A large number of differentially expressed genes (DEGs) were identified including jointly up-regulated genes (263) and down-regulated genes (378). JA synthesis and signaling transduction, terpene biosynthesis, and MAPKs signaling pathway were analyzed in depth and found that <jats:italic>TcOPR3, TcJAR1, TcJAZs</jats:italic>, and <jats:italic>TcTPS9</jats:italic> genes possessed anti-insect potential. Moreover, MYB and ERF transcription factor (TF) families were significantly strengthened to the point that they may participate in induced defense mechanisms in <jats:italic>T. ciliata</jats:italic>. These data not only provide insights into the molecular mechanisms in resistance of <jats:italic>T. ciliata</jats:italic> to HRM but also helps to explore the new biocontrol strategies against insects in eco-friendly woody plants.</jats:p>

<jats:p>As a one of the focuses of ecological research, understanding the regulation of plant diversity on community stability is helpful to reveal the adaption of plant to environmental changes. However, the relationship between plant diversity and community stability is still controversial due to the scale effect of its influencing factors. In this study, we compared the changes in community stability and different plant diversity (i.e., species, functional, and phylogenetic diversities) between three communities (i.e., riparian forest, ecotone community, and desert shrubs), and across three spatial scales (i.e., 100, 400, and 2500 m<jats:sup>2</jats:sup>), and then quantified the contribution of soil properties and plant diversity to community stability by using structural equation model (SEM) in the Ebinur Lake Basin Nature Reserve of the Xinjiang Uygur Autonomous Region in the NW China. The results showed that: (1) community stability differed among three communities (ecotone community &amp;gt; desert shrubs &amp;gt; riparian forest). The stability of three communities all decreased with the increase of spatial scale (2) species diversity, phylogenetic richness and the mean pairwise phylogenetic distance were higher in ecotone community than that in desert shrubs and riparian forest, while the mean nearest taxa distance showed as riparian forest &amp;gt; ecotone community &amp;gt; desert shrubs. (3) Soil ammonium nitrogen and total phosphorus had the significant direct negative and positive effects on the community stability, respectively. Soil ammonium nitrogen and total phosphorus also indirectly affected community stability by adjusting plant diversity. The interaction among species, functional and phylogenetic diversities also regulated the variation of community stability across the spatial scales. Our results suggested that the effect of plant diversities on community stability were greater than that of soil factors. The asynchronous effect caused by the changes in species composition and functional traits among communities had a positive impact on the stability. Our study provided a theoretical support for the conservation and management of biodiversity and community functions in desert areas.</jats:p>

<jats:p>Floral nectar contains mainly sugars as well as smaller amounts of amino acids and further compounds. The nectar composition varies between different plant species and it is related to the pollination type of the plant. In addition to this, other factors can influence the composition. Nectar is produced in and secreted from nectaries. A few models exist to explain the origin of nectar for dicotyl plant species, a complete elucidation of the processes, however, has not yet been achieved. This is particularly true for monocots or plant species with CAM photosynthesis. To get closer to such an elucidation, nectar, nectaries, and leaves of 36 bromeliad species were analyzed for sugars, starch, amino acids, and inorganic ions. The species studied include different photosynthesis types (CAM/C3), different pollination types (trochilophilous/chiropterophilous), or different live forms. The main sugars in nectar and nectaries were glucose, fructose, and sucrose, the total sugar concentration was about twofold higher in nectar than in nectaries, which suggests that sugars are actively transported from the nectaries into the nectar. The composition of amino acids in nectar is already determined in the nectaries, but the concentration is much lower in nectar than in nectaries, which suggests selective retention of amino acids during nectar secretion. The same applies to inorganic ions. Statistical analyses showed that the photosynthesis type and the pollination type can explain more data variation in nectar than in nectaries and leaves. Furthermore, the pollinator type has a stronger influence on the nectar or nectary composition than the photosynthesis type. Trochilophilous C3 plants showed significant correlations between the nitrate concentration in leaves and the amino acid concentration in nectaries and nectar. It can be assumed that the more nitrate is taken up, the more amino acids are synthesized in leaves and transported to the nectaries and nectar. However, chiropterophilous C3 plants show no such correlation, which means that the secretion of amino acids into the nectar is regulated by further factors. The results help understand the physiological properties that influence nectaries and nectar as well as the manner of metabolite and ion secretion from nectaries to nectar.</jats:p>