The Epidermal Patterning Factor/EPF-like (EPF/EPFL) family encodes a specific type of secreted protein in plants and plays an important role in plant growth and development, especially in the process of morphogenesis. To investigate the characteristics of EPF/EPFL gene family members and their regulatory functions in stomatal development of Populus trichocarpa, a total of 15 EPF/EPFL family genes were identified. Then the gene structure, chromosome location, phylogenetic relationship, protein conserved domain and gene expression profile were analyzed. According to phylogenetic analysis, PtEPF/EPFL can be classified into four groups. The gene structure and protein conservation motifs within the EPF family indicate the high conservation of the PtEPF/EPFL sequence. The promoter region of PtEPF/EPFL was found to contain cis-elements in response to stress and plant hormones. In addition, RT-qPCR results indicated that the PtEPF/EPFL have a differentially expressed in different tissues. Under drought stress treatment, a substantial upregulation was observed in the majority of PtEPF/EPFL members, suggesting their potential involvement in drought response. These results provide a theoretical basis for future exploration of the characteristics and functions of more PtEPF/EPFL genes.

Background/Objectives: Nitrogen is an essential macroelement for plant growth and productivity. Calcium (Ca2+) acts as a critical second messenger in numerous adaptations and developmental processes in plants. The Calcineurin B-like protein (CBL)-interacting protein kinase (CIPK) signaling pathway has been demonstrated to be involved in multiple intracellular ion homeostasis of plants in response to stresses. However, whether CIPKs are involved in nitrate deficiency stress remains largely unknown. Methods: In this study, we screened Arabidopsis thaliana T-DNA insertion mutants of the CIPK family under nitrate deficiency conditions by a reverse genetic strategy. Results: We found that the cipk1 mutant showed a shorter primary root and had a lower fresh weight and total N content compared with wildtype (WT) plants under nitrate deficiency. The CIPK1 complementation lines completely rescued the sensitive phenotype. Additionally, CIPK1 mutation caused nitrogen-starvation marker genes to be decreased under nitrate deficiency. We further found that CIPK1 interacted with teosintebranched 1/cycloidea/proliferating cell factor 1-20 (TCP20) in a yeast two-hybrid system. Conclusions: Collectively, our results reveal a novel role of CIPK1 in response to nitrate deficiency in Arabidopsis.

Peppers (Capsicum annuum L.), as a horticultural crop with one of the highest ascorbic acid contents, are negatively affected by detrimental environmental conditions both in terms of quality and productivity. In peppers, the high level of ascorbic acid is not only a nutrient substance but also plays a role in environmental stress, i.e., drought stress. When suffering from drought stress, plants accumulate dehydrins, which play important roles in the stress response. Here, we isolated an SK3-type DHN gene CaDHN2 from peppers. CaDHN2 was located in the nucleus, cytoplasm, and cell membrane. In CaDHN2-silenced peppers, which are generated by virus-induced gene silencing (VIGS), the survival rate is much lower, the electrolytic leakage is higher, and the accumulation of reactive oxygen species (ROS) is greater when compared with the control under drought stress. Moreover, when CaDHN2 (CaDHN2-OE) is overexpressed in Arabidopsis, theoverexpressing plants show enhanced drought tolerance, increased antioxidant enzyme activities, and lower ROS content. Based on yeast two-hybrid (Y2H), GST-pull down, and bimolecular fluorescence complementation (BiFC) results, we found that CaDHN2 interacts with CaGGP1, the key enzyme in ascorbic acid (AsA) synthesis, in the cytoplasm. Accordingly, the level of ascorbic acid is highly reduced in CaDHN2-silenced peppers, indicating that CaDHN2 interacts with CaGGP1 to affect the synthesis of ascorbic acid under drought stress, thus improving the drought tolerance of peppers. Our research provides a basis for further study of the function of DHN genes.

Chinese jujube (Ziziphus jujuba Mill.) is a globally popular and economically important fruit that is rich in bioactive compounds with strong anti-cancer effects. Rain-proof cultivation is widely used to cultivate Chinese jujube, as it helps avoid rainfall damage during fruit harvest. Although the sugar content of jujube fruits differs between rain-proof and open-field cultivation, the underlying molecular mechanisms are unknown. Here, we analyzed the levels of sugar content, sugar accumulation pattern, and transcriptome profiles of jujube fruits at five developmental stages grown under rain-proof and open-field cultivation modes. The sugar content of jujube fruits was significantly higher under rain-proof cultivation than under open-field cultivation, although the sugar composition and sugar accumulation patterns were comparable. Comparative analysis of transcriptomic profiles showed that rain-proof cultivation enhanced the intrinsic metabolic activity of fruit development. Gene expression and correlation analyses suggested that ZjSPS, ZjSS, ZjHXK, and ZjINV regulate the development-related changes in sugar content in jujube fruits grown under rain-proof cultivation. Temperature, humidity, and moisture conditions were key climatic factors affecting sugar accumulation. Our results provide insights into the molecular mechanisms regulating sugar content and sugar accumulation in Chinese jujube fruits grown under rain-proof cultivation, and we provide genetic resources for studying the development mechanism of Chinese jujube fruit.

Subject of this paper is the Abies georgei var. smithii forest in the Shergyla mountain of Tibet, China. With environmental factor, ecosystem stability, ecosystem diversity, and ecosystem structure as evaluation criteria, this paper built an Evaluation Index System (EIS) with 12 indexes of 4 categories and 2 levels and employed the Fuzzy Comprehensive Evaluation (FCE) method to assess the health status of the target forest. The research results revealed that, among the 25 surveyed sample plots of Abies georgei var. smithii forest, 18 plots are in a healthy or sub-healthy status, accounting for 72% of the total plots, and 8% of the plots are in an unhealthy status. Main factors that affect the forest health conditions include the number of seedlings, species richness, and species diversity, etc.