Salt stress is a significant environmental factor that impedes maize growth and yield. Exogenous 5-aminolevulinic acid (ALA) has been shown to mitigate the detrimental effects of various environmental stresses on plants. However, its regulatory role in the photosynthesis mechanisms of maize seedlings under salt stress remains poorly understood. Transcriptome sequencing and physiological index measurements were conducted on the leaves of the “Zhengdan 958” cultivar subjected to three different treatments. Differential expression analysis revealed 4634 differentially expressed genes (DEGs), including key transcription factor (TF) families such as NAC, MYB, WRKY, and MYB-related, across two comparisons (SS_vs_CK and ALA_SS_vs_SS). Significant enrichment was observed in the metabolic pathways related to porphyrin metabolism, photosynthesis-antenna proteins, photosynthesis, and carbon fixation in photosynthetic organisms. ALA treatment modulated the expression of photosynthesis-related genes, increased photosynthetic pigment content, and enhanced the activities of superoxide dismutase (SOD) and catalase (CAT), thereby mitigating the excessive accumulation of reactive oxygen species (ROS). Furthermore, ALA increased starch content under salt stress. These findings establish a foundational understanding of the molecular mechanisms through which ALA regulates photosynthesis under salt stress in maize seedlings. Collectively, exogenous ALA enhances maize’s salt tolerance by regulating photosynthesis-related pathways.

Drought is one of the most detrimental environmental factors restricting the growth of wheat (Triticum aestivum L.). The investigation of the impact of uniconazole on carbon metabolism in wheat seedlings under drought stress could provide new insights into wheat stress physiology and tolerance. The effects of uniconazole (30 mg L⁻¹) on wheat drought tolerance were investigated via a physiological analysis of the wheat genotypes ‘Wansu 1510’ (WS1510) and ‘Huacheng wheat 1688’ (HC1688) under a 15% polyethylene glycol (PEG) and 30% PEG treatment and a transcriptome analysis of ‘Wansu 1510’ (WS1510) under a 30% PEG treatment. The results revealed that uniconazole significantly increased the leaf relative water content (RWC), reduced plant height, and counteracted the reduction in fresh weight and root length under drought stress. It inhibited the excessive accumulation of reactive oxygen species (ROS) and protected against membrane lipid peroxidation caused by drought stress by regulating superoxide dismutase (SOD) gene expression, enhancing antioxidant enzymes activities, and adjusting the content of osmoregulatory compounds in drought-stressed plants. Furthermore, uniconazole treatment increased chlorophyll (Chl) and carotenoid (Car) contents, inhibited the increase in sucrose concentration, and alleviated the reduction in starch content due to increased sucrose synthase (SS) activity under drought stress. Transcriptome sequencing revealed that uniconazole regulated the expression of genes associated with starch and sucrose metabolism, porphyrin and chlorophyll metabolism, the photosynthetic antenna proteins, carotenoid biosynthesis, and carbon fixation in photosynthetic organisms, which are involved in carbon metabolism processes and photosynthetic pigment production and which regulate the conversion of sucrose and starch under drought stress. Our findings emphasize the importance of exogenous uniconazole in regulating carbon metabolism in wheat.

Salt stress is a significant environmental factor influencing plant growth and development. Anoectochilus roxburghii is a valuable medicinal plant, but it is still unclear how it responds to salinity. In this study, A. roxburghii was used as experimental material to investigate its physiological mechanisms underlying salt stress resistance. Seedlings were subjected to various NaCl concentrations (0, 50, 100, 150, and 200 mmol/L), and changes in key physiological parameters were subsequently analyzed. The results indicated that under NaCl-induced salt stress, the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), as well as soluble protein content, initially increased and then decreased, with peak levels observed between 100 and 150 mmol/L. Malondialdehyde (MDA) content exhibited a steady increase with rising salt concentration. Total chlorophyll content declined progressively, while anthocyanin content increased initially but decreased significantly when NaCl concentration exceeded 100 mmol/L. Additionally, the contents of total flavonoids and total phenolics decreased markedly at salt concentrations above 100 mmol/L. These findings suggest that A. roxburghii can tolerate salt stress up to 100 mmol/L for 24 h without exhibiting substantial physiological or morphological damage. This study provides a theoretical basis for analyzing the salt tolerance mechanism of A. roxburghii.

The multidrug and toxic compound extrusion (MATE) family is the latest class of novel secondary transporters discovered in plants. However, there is currently no comprehensive analysis of the MATE gene family in the tea plant. In this study, 68 CsMATE genes were identified from the tea plant genome using bioinformatic methods. In general, we analyzed the evolutionary relationships, intron–exon structure, distribution in chromosomes, conserved domains, and gene expression patterns in different tissues and stresses of the CsMATE gene family. The 68 CsMATEs were phylogenetically divided into four major clusters (Class I to Class IV). The CsMATE genes within the same class exhibit similar structural features, while displaying certain distinctions across different classes. Evolutionary analysis indicated that the CsMATE gene family expanded mainly through gene duplication events, in addition to proximal duplication. Through the analysis of cis-acting elements, it was found that CsMATE genes may be involved in the growth, development, and stress response. Furthermore, we observed that certain CsMATE genes could be induced to exhibit expression under abiotic stress conditions such as low temperature, high salinity (NaCl), osmotic stress (PEG), and methyl jasmonate treatment (MeJA). The findings presented herein offer a crucial theoretical foundation for elucidating the biological functions of CsMATE genes, particularly in response to abiotic stress, and furnish valuable potential genetic resources for tea plant resistance breeding.