Increasing drought and soil salinity pose significant threats to crop production around the world. One potential strategy to mitigate the impacts of these environmental changes is grafting, a horticultural technique that joins tissues from different plants. This study aimed to investigate and model changes in the expression of NAC and WRKY genes in grafted watermelon under varying salt and drought stress conditions (mild to extrem). The control groups were not restricted by any limitations. Citrullus lanatus (Thunb.) Matsum. & Nakai (watermelon) was used as the scion, and Lagenaria siceraria (Molina) Standl (bottle gourd) served as the rootstock in our experiments. During the 14-day treatment period, individuals from the grafted watermelon and bottle gourd plants were more successful to maintained water balance and growth rates, while ungrafted plants exhibited growth retardation and tissue damage, especially under salt stress. The analysis of gene expression revealed that grafted plants showed significantly increased expression of salt- and drought-sensitive genes, including ClNAC2b, ClNAC69, ClNAC72, ClWRKY13, ClWRKY14, and ClWRKY23, compared to ungrafted plants under low-stress conditions. These adaptations, such as stomatal closure and regulation of evaporation, enabled the improved grafted plants to respond more effectively to abiotic stress, supporting their survival and normal development. Our findings underscore that grafting is an environmentally friendly, rapid, and effective technique to enhance plant resilience against abiotic stresses, offering promising avenues to improve stable food crop production amidst increasing environmental challenges.

Heavy metals in soil can inflict direct damage on plants growing within it, adversely affecting their growth height, root development, leaf area, and other physiological traits. To counteract the toxic impacts of heavy metals on plant growth and development, plants mitigate heavy metal stress through mechanisms such as metal chelation, vacuolar compartmentalization, regulation of transporters, and enhancement of antioxidant functions. WRKY transcription factors (TFs) play a crucial role in plant growth and development as well as in responses to both biotic and abiotic stresses; notably, heavy metal stress is classified as an abiotic stressor. An increasing number of studies have highlighted the significant role of WRKY proteins in regulating heavy metal stress across various levels. Upon the entry of heavy metal ions into plant root cells, the production of reactive oxygen species (ROS) is triggered, leading to the phosphorylation and activation of WRKY TFs through MAPK cascade signaling. Activated WRKY TFs then modulate various physiological processes by upregulating or downregulating the expression of downstream genes to confer heavy metal tolerance to plants. This review provides an overview of the research advancements regarding WRKY TFs in regulating heavy metal ion stress-including cadmium (Cd), arsenic (As), copper (Cu)-and aluminum (Al) toxicity.

Soil salinity caused by NaCl is a major challenge to agricultural crops worldwide. For this, two WRKY transcription factors were evaluated for their role in salt stress tolerance in tomato plants ( Solanum lycopersicum; ; Sl ). SlWRKY36 and SlWRKY51 provided novel insight into the regulatory mechanism in tomato against salt stress via virus-induced gene silencing (VIGS). Salt stress significantly reduced chlorophyll-a, an abundant form of chlorophyll content to 6.0 and 5.1 mg/g and proline content to 0.06 mg/g and 0.09 mg/g respectively in SlWRKY36 and SlWRKY51 silenced tomato plants. This shows that salt stress affected proline content that act as osmoprotectant and damaged photosynthetic pigments in silenced SlWRKY36 and SlWRKY51 tomato plants. Similarly, the concentrations of Na+/ + / K+ + ratio also showed a significantly higher trend 14 days after salt stress with 5.5 mg/g and 8.9 mg/g concentration at 200 mM for SlWRKY36 and SlWRKY51 showing silencing promotes Na+/K+ +/K + ion ratio under salt stress. Also, salt stress responsive genes such as salt overly sensitive SOS1 and Na+/ +/ H+ + exchanger NHX1 displayed lower transcript level in silenced plants at 200 mM salt stress showing their negative regulation by SlWRKY36 and SlWRKY51 gene silencing. Collectively, these findings suggest for the first time the role of SlWRKY36 and SlWRKY51 as positive regulators of salt stress tolerance by managing ion homeostasis, proline content and photosynthetic machinery via transcriptional reprogramming. Overall, SlWRKY36 and SlWRKY51 were explored as potential candidates for engineering salt tolerance in tomato crop plants.

Cadmium (Cd) is a heavy metal highly toxic to living organisms. Cd pollution of soils has become a serious problem worldwide, posing a severe threat to crop production and human health. When plants are poisoned by Cd, their growth and development are inhibited, chloroplasts are severely damaged, and respiration and photosynthesis are negatively affected. Therefore, elucidating the molecular mechanisms that underlie Cd tolerance in plants is important. Transcription factors can bind to specific plant cis-acting genes. Transcription factors are frequently reported to be involved in various signaling pathways involved in plant growth and development. Their role in the resistance to environmental stress factors, particularly Cd, should not be underestimated. The roles of several transcription factor families in the regulation of plant resistance to Cd stress have been widely demonstrated. In this review, we summarize the mechanisms of five major transcription factor families-WRKY, ERF, MYB, bHLH, and bZIP-in plant resistance to Cd stress to provide useful information for using molecular techniques to solve Cd pollution problems in the future.