Yong Qin

As natural environments degrade and extreme weather events become more frequent, humanity increasingly faces the challenge of producing crops under various complex and adverse conditions. Improving crop adaptability has become crucial. Universal stress proteins (USPs) are a class of small molecular proteins widely found in plants, capable of withstanding various biotic and abiotic environmental stresses, including temperature stress, drought, nutrient deficiency, oxidative imbalance, salt and heavy ion toxicity, and pathogenic infections. Enhancing our understanding of USPs holds significant potential for improving plant stress resilience. This study focuses on 13 species of Solanum, including cultivated and wild tomatoes, and systematically identified 438 members of the USP gene family through bioinformatics approaches. Phylogenetic analysis reveals that major USP members are conserved within Solanum, with interspecies differences in USP numbers primarily attributed to copy number variation (CNV). Through synteny and homology analyses, we found that USP27 and USP28 are unique to tomatoes, while the homologous gene of USP19 is absent in cultivated tomatoes. Notably, five unique USP genes are present in S. pennellii, which is characterized by its early differentiation and resistance advantages. Ka/Ks analysis indicates that only the USP10/21 homologous gene pair has undergone positive selection in wild tomatoes, while all other genes are subject to strong negative selection. The USPs in Solanum exhibit high consistency in domain characteristics, sequence conservation, and types of promoter regulatory elements, although there are substantial differences in the number of these elements. Utilizing publicly available data, we identified eight USPs that have undergone domestication or improvement selection, particularly noting the tissue-specific expression patterns of domesticated SolycUSP3/28/30. Through graph pangenome analysis, we screened 12 USPs covered by high-confidence structural variants, which primarily disrupt the intron regions of USPs, leading to significant differences in their expression responses to salt stress. We anticipate that these findings will provide a theoretical foundation and prior knowledge for further understanding and application of USP in plants.

Lettuce is susceptible to high-temperature stress during cultivation, leading to bolting and affecting yield. Plant-specific transcription factors, known as GRAS proteins, play a crucial role in regulating plant growth, development, and abiotic stress responses. In this study, the entire lettuce LsGRAS gene family was identified. The results show that 59 LsGRAS genes are unevenly distributed across the nine chromosomes. Additionally, all LsGRAS proteins showed 100% nuclear localization based on the predicted subcellular localization and were phylogenetically classified into nine conserved subfamilies. To investigate the expression profiles of these genes in lettuce, we analyzed the transcription levels of all 59 LsGRAS genes in the publicly available RNA-seq data under the high-temperature treatment conducted in the presence of exogenous melatonin. The findings indicate that the transcript levels of the LsGRAS13 gene were higher on days 6, 9, 15, 18, and 27 under the high-temperature (35/30 °C) treatment with melatonin than on the same treatment days without melatonin. The functional studies demonstrate that silencing LsGRAS13 accelerated bolting in lettuce. Furthermore, the paraffin sectioning results showed that flower bud differentiation in LsGRAS13-silenced plants occurred significantly faster than in control plants. In this study, the LsGRAS genes were annotated and analyzed, and the expression pattern of the LsGRAS gene following melatonin treatment under high-temperature conditions was explored. This exploration provides valuable information and identifies candidate genes associated with the response mechanism of lettuce plants high-temperature stress.

Coreopsis tinctoria, as a medicinal plant, has become popular in China in the past decade. However, basic data on NO₃⁻ supply related to its production and nitrogen (N) metabolism are lacking. In this study, all plants were grown to four leaves in substrate (vermiculite:perlite = 2:1), which were subsequently transferred to different reducing NO₃⁻ solutions. Appropriate N fertilizer application reductions (1/8N-1/2N) maintained the flower number and biomass of Coreopsis tinctoria during 2020–2021. N fertilizer reduction maintained the N assimilation levels of C. tinctoria and increased N use efficiency (NUE), one of the important reasons was that the reduction of N fertilizer did not damage the chlorophyll fluorescence system and photosynthetic system. 1/2N-1/8N treatment also maintained the activities nitrate reductase (NR), nitrite reductase (NIR), glutamine synthase (GS) and glutamate synthase (GOGAT) and the content of total amino acid and soluble protein in leaves. N reduction treatment also increased the levels of tyrosine (Thr), serine (Ser), leucine (Leu), isoleucine (Ile), lysine (Lys) and arginine (Arg) of leaves in C. tinctoria, and further enhances N assimilation ability. Leaf N content was significantly correlated with the activities of NR, NIR, GS, GOGAT and GDH, indicating that N metabolism was effectively regulated by N levels. In conclusion, the 1/8 N level prior to harvest could be one of the strategies for C. tinctoria cultivation because it minimizes planting costs and maintains nitrogen assimilation capacity and productivity.

Coreopsis tinctoria Nutt. (C. tinctoria) has a long history of application and high economic and medicinal value. Flavonoids, the main active components of C. tinctoria, are widely studied in pharmacology and food development. However, the flavonoid biosynthesis pathway in C. tinctoria is unclear. In this study, we comprehensively compared the transcriptomes and metabolite profiles of two colors of C. tinctoria flowers (LS and JS) at different flowering stages. A total of 165 flavonoids (46 flavonoids, 42 flavonols, 22 anthocyanins, 18 chalcones, 12 dihydroflavonols, nine isoflavones, eight dihydroflavonoids, six flavanols, and two tannins) were identified in LS and JS at different flowering stages. Thirty-three metabolites (11 anthocyanins, 11 flavonols, seven flavonoids, two dihydroflavonols, one dihydroflavone, and one chalcone) were found to be statistically significantly different in the LS vs. JS groups. LS flowers accumulated higher levels of 10 anthocyanins (seven cyanidins and three pelargonidins) than JS flowers. Furthermore, candidate genes related to the regulation of flavonoid and anthocyanin synthesis were identified and included 28 structural genes (especially F3H, Cluster-28756.299649, and 3GT, Cluster-28756.230942) in LS and JS, six key differentially expressed transcription factors (especially MYB90a, Cluster-28756.143139) in LS and JS, and 17 other regulators (mainly including transporter proteins and others) in LS. Our results provide valuable information for further studies on the mechanism underlying flavonoid biosynthesis in C. tinctoria.

Salt stress causes the quality change and significant yield loss of tomato. However, the resources of salt-resistant tomato were still deficient and the mechanisms of tomato resistance to salt stress were still unclear. In this study, the proteomic profiles of two salt-tolerant and salt-sensitive tomato cultivars were investigated to decipher the salt-resistance mechanism of tomato and provide novel resources for tomato breeding. We found high abundance proteins related to nitrate and amino acids metabolismsin the salt-tolerant cultivars. The significant increase in abundance of proteins involved in Brassinolides and GABA biosynthesis were verified in salt-tolerant cultivars, strengthening the salt resistance of tomato. Meanwhile, salt-tolerant cultivars with higher abundance and activity of antioxidant-related proteins have more advantages in dealing with reactive oxygen species caused by salt stress. Moreover, the salt-tolerant cultivars had higher photosynthetic activity based on overexpression of proteins functioned in chloroplast, guaranteeing the sufficient nutrient for plant growth under salt stress. Furthermore, three key proteins were identified as important salt-resistant resources for breeding salt-tolerant cultivars, including sterol side chain reductase, gamma aminobutyrate transaminase and starch synthase. Our results provided series valuable strategies for salt-tolerant cultivars which can be used in future.

Flavonoids are phytochemicals present in medicinal plants and contribute to human health. Coreopsis tinctoria, a species rich in flavonoids, has long been used in traditional medicine and as a food resource. N (nitrogen) fertilization can reduce flavonoid accumulation in C. tinctoria. However, there is limited knowledge regarding N regulatory mechanisms. The aim of this study was to determine the effect of N availability on flavonoid biosynthesis in C. tinctoria and to investigate the relationship between C (carbon) and N metabolism coupled with flavonoid synthesis under controlled conditions. C. tinctoria seedlings were grown hydroponically under five different N levels (0, 0.625, 1.250, 2.500 and 5.000 mM). The related indexes of C, N and flavonoid metabolism of C. tinctoria under N variation were measured and analysed. N availability (low and moderate N levels) regulates enzyme activities related to C and N metabolism, promotes the accumulation of carbohydrates, reduces N metabolite levels, and enhances the internal C/N balance. The flavonoid content in roots and stalks remained relatively stable, while that in leaves peaked at low or intermediate N levels. Flavonoids are closely related to phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate: coenzyme A ligase (4CL), and chalcone-thioase (CHS) activity, significantly positively correlated with carbohydrates and negatively correlated with N metabolites. Thus, C and N metabolism can not only control the distribution of C in amino acid and carbohydrate biosynthesis pathways but also change the distribution in flavonoid biosynthesis pathways, which also provides meaningful information for maintaining high yields while ensuring the nutritional value of crop plants.

Coreopsis tinctoria Nutt. ( C. tinctoria ) is used in composite tea material and has important medicinal functions. Soil salinization affects the growth and development of C. tinctoria in Xinjiang (China). Here, we discussed the changes in photosynthesis and physiological characteristics of C. tinctoria seedlings treated with different concentrations of NaCl [0 (CK), 50, 100, 150, 200, and 250 mmol·L ⁻¹ ] for 12, 24, and 72 hours. The results showed that the net photosynthetic rate (P _n ), stomatal conductance ( g _S ), transpiration rate (T _r ), and stomatal inhibition rate (L _s ) decreased significantly with increasing concentrations of NaCl. Salt stress promoted the accumulation of peroxidase (POD), catalase (CAT), soluble sugar, soluble protein, and free proline (Pro). A highly significant positive correlation was found between L _s and F _v /F _m ; L _s and F _v /F _o ; soluble sugar and CAT; soluble sugar and soluble protein. C. tinctoria was most sensitive to the concentrations of 150 to 250 mmol·L ⁻¹ NaCl, and its salt stress tolerance was increased by reducing photosynthetic fluorescence parameters, improving the antioxidant enzyme system, and regulating osmotic substances.

Coreopsis tinctoria Nutt. (C. tinctoria) is a special tea ingredient that adapts to certain salt stresses and shares the functions of chrysanthemum. With annual expansion of the cultivation area of C. tinctoria in Xinjiang (China), soil salinity may become a constraint for chrysanthemum cultivation. To investigate the response of C. tinctoria to salt stress, physiological and transcriptional changes in C. tinctoria in the early stages of low (50 mM NaCl) and high (200 mM NaCl) salt stress were analyzed and identified. The results showed that the contents of osmotic regulators (free proline, soluble sugar, and soluble protein) and antioxidant enzymes (catalase and peroxidase) under salt stress increased to various extents compared with those of the control (CK) within 72 h, and the increase was higher under 200 mM NaCl treatments. De novo RNA-seq was used to analyze changes in the transcripts under 50 and 200 mM NaCl treatments for up to 48 h. In total, 8,584, 3,760, 7,833, 19,341, 13,233, and 9,224 differentially expressed genes (DEGs) were detected under 12 h, 24 h, and 48 h for 50 and 200 mM NaCl treatments, respectively. Weighted correlation network analysis (WGCNA) was used to analyze the correlations between all DEGs and physiological indexes. We found that the coexpression modules blue2 and Lightskyblue4 highly correlated with osmotic regulators and CAT and identified 20 and 30 hub genes, respectively. The results provide useful data for the further study of salt tolerance in C. tinctoria.