Primary plant nutrients modulate the reactive oxygen species metabolism and mitigate the impact of cold stress in overseeded perennial ryegrass

VvERF117 positively regulates grape cold tolerance through direct regulation of the antioxidative gene BAS1

Cold stress significantly threatens grape quality, yield, and geographical distribution. Although ethylene-responsive factors (ERFs) are recognized for their pivotal roles in cold stress, the regulatory mechanisms of many ERFs contributing to tolerance remain unclear. In this study, we identified the cold-responsive gene VvERF117 and elucidated its positive regulatory function in cold tolerance. VvERF117 exhibits transcriptional activity and localizes to the nucleus. VvERF117 overexpression improved cold tolerance in transgenic Arabidopsis, grape calli, and grape leaves, whereas VvERF117 silencing increased cold sensitivity in grape calli and leaves. Furthermore, VvERF117 overexpression remarkably upregulated the expression of several stress-related genes. Importantly, BAS1, encoding a 2-Cys peroxidase (POD), was confirmed as a direct target gene of VvERF117. Meanwhile, compared to the wild-type, POD activity and H2O2 content were remarkably increased and decreased in VvERF117-overexpressing grape calli and leaves, respectively. Conversely, VvERF117 silencing displayed the opposite trend in grape calli and leaves under cold stress. These findings indicate that VvERF117 plays a positive role in cold resistance by, at least in part, enhancing antioxidant capacity through regulating the POD-encoding gene VvBAS1, leading to effective mitigation of reactive oxygen species.

Assessing the effect of soil cultivation methods and genotypes on crop yield components, yield and soil properties in wheat (Triticum aestivum L.) and Rice (Oryza sativa L.) cropping system

BACKGROUND

The rice-wheat cropping system is the prevailing agricultural method in the North-Western states of India, namely in the Indo-Gangetic plains. The practice of open burning of rice residue is frequently employed for expedient land preparation, but it has significant adverse impacts on both the environment and human health. These include the emission of greenhouse gases, loss of nutrients, elevated concentrations of particulate matter (PM), and disruption of the biological cycle. This research aims to investigate the implementation of effective management strategies in the rice-wheat cropping system, namely via the use of tillage-based crop cultivation techniques, stubble retention, and integration approaches. The objective is to enhance soil health features in order to augment crop yield and improve its attributes.

RESULTS

The research was carried out using a split plot experimental design, consisting of three replications. The main plot consisted of four different cultivation methods, while the subplot included three genotypes of both rice and wheat. The research demonstrates the enhanced efficacy of residue application is significantly augmenting soil nutrient concentrations compared to standard tillage practices (P < 0.05). This was accomplished by an analysis of soil nutrient levels, namely nitrogen (N), phosphorus (P), potassium (K), and organic carbon (OC), at a depth of 0-15 cm. The implementation of natural farming, zero tillage, and reduced tillage practices resulted in decreases in rice grain yields of 34.0%, 16.1%, and 10.8%, respectively, as compared to conventional tillage methods. Similarly, the implementation of natural farming, zero tillage, and reduced tillage resulted in reductions in wheat grain yields of 59.4%, 10.9%, and 4.6% respectively, in comparison to conventional tillage practices.

CONCLUSION

Regarding the individual crop genotypes investigated, it was continuously observed that Him Palam Lal Dhan 1 and HPW 368 displayed considerably greater grain yields for both rice and wheat during the two-year experimental period. Furthermore, when considering different cultivation methods, conventional tillage emerged as the most effective approach for obtaining higher productivity in both rice and wheat. Additionally, Him Palam Lal Dhan 1 and HPW 368 exhibited superior performance in terms of various crucial yield components for rice (such as panicle density, grains per panicle, panicle weight, and test weight) and wheat (including effective tiller density, grains per spike, spike weight, and 1000-grain weight).

Integrative application of silicon and/or proline improves Sweet corn (Zea mays L. saccharata) production and antioxidant defense system under salt stress condition

Silicon (Si) and/or proline (Pro) are natural supplements that are considered to induce plants' stress tolerance against various abiotic stresses. Sweet corn (Zea mays L. saccharata) production is severely afflicted by salinity stress. Therefore, two field tests were conducted to evaluate the potential effects of Si and/or Pro (6mM) used as seed soaking (SS) and/or foliar spray (FS) on Sweet corn plant growth and yield, physio-biochemical attributes, and antioxidant defense systems grown in a saline (EC = 7.14dS m-1) soil. The Si and/or Pro significantly increased growth and yield, photosynthetic pigments, free proline, total soluble sugars (TSS), K+/Na+ratios, relative water content (RWC), membrane stability index (MSI), α-Tocopherol (α-TOC), Ascorbate (AsA), glutathione (GSH), enzymatic antioxidants activities and other anatomical features as compared to controls. In contrast, electrolytes, such as SS and/or FS under salt stress compared to controls (SS and FS using tap water) were significantly decreased. The best results were obtained when SS was combined with FS via Si or Pro. These alterations are brought about by the exogenous application of Si and/or Pro rendering these elements potentially useful in aiding sweet corn plants to acclimate successfully to saline soil.

Differential Regulations of Antioxidant Metabolism and Cold-Responsive Genes in Three Bermudagrass Genotypes under Chilling and Freezing Stress

As a typical warm-season grass, bermudagrass growth and turf quality begin to decrease when the environmental temperature drops below 20 °C. The current study investigated the differential responses of three bermudagrass genotypes to chilling stress (8/4 °C) for 15 days and then freezing stress (2/-2 °C) for 2 days. The three genotypes exhibited significant variation in chilling and freezing tolerance, and Chuannong-3, common bermudagrass 001, and Tifdwarf were ranked as cold-tolerant, -intermediate, and -sensitive genotypes based on evaluations of chlorophyll content, the photochemical efficiency of photosystem II, oxidative damage, and cell membrane stability, respectively. Chuannong-3 achieved better tolerance through enhancing the antioxidant defense system to stabilize cell membrane and reactive oxygen species homeostasis after being subjected to chilling and freezing stresses. Chuannong-3 also downregulated the ethylene signaling pathway by improving CdCTR1 expression and suppressing the transcript levels of CdEIN3-1 and CdEIN3-2; however, it upregulated the hydrogen sulfide signaling pathway via an increase in CdISCS expression under cold stress. In addition, the molecular basis of cold tolerance could be associated with the mediation of key genes in the heat shock pathway (CdHSFA-2b, CdHSBP-1, CdHSP22, and CdHSP40) and the CdOSMOTIN in Chuannong-3 because the accumulation of stress-defensive proteins, including heat shock proteins and osmotin, plays a positive role in osmoprotection, osmotic adjustment, or the repair of denatured proteins as molecular chaperones under cold stress. The current findings give an insight into the physiological and molecular mechanisms of cold tolerance in the new cultivar Chuannong-3, which provides valuable information for turfgrass breeders and practitioners.

Role of melatonin in enhancing arbuscular mycorrhizal symbiosis and mitigating cold stress in perennial ryegrass (Lolium perenne L.)

Melatonin is a biomolecule that affects plant development and is involved in protecting plants from environmental stress. However, the mechanisms of melatonin's impact on arbuscular mycorrhizal (AM) symbiosis and cold tolerance in plants are still unclear. In this research, AM fungi inoculation and exogenous melatonin (MT) were applied to perennial ryegrass (Lolium perenne L.) seedlings alone or in combination to investigate their effect on cold tolerance. The study was conducted in two parts. The initial trial examined two variables, AM inoculation, and cold stress, to investigate the involvement of the AM fungus Rhizophagus irregularis in endogenous melatonin accumulation and the transcriptional levels of its synthesis genes in the root system of perennial ryegrass under cold stress. The subsequent trial was designed as a three-factor analysis, encompassing AM inoculation, cold stress, and melatonin application, to explore the effects of exogenous melatonin application on plant growth, AM symbiosis, antioxidant activity, and protective molecules in perennial ryegrass subjected to cold stress. The results of the study showed that compared to non-mycorrhizal (NM) plants, cold stress promoted an increase in the accumulation of melatonin in the AM-colonized counterparts. Acetylserotonin methyltransferase (ASMT) catalyzed the final enzymatic reaction in melatonin production. Melatonin accumulation was associated with the level of expression of the genes, LpASMT1 and LpASMT3. Treatment with melatonin can improve the colonization of AM fungi in plants. Simultaneous utilization of AM inoculation and melatonin treatment enhanced the growth, antioxidant activity, and phenylalanine ammonia-lyase (PAL) activity, while simultaneously reducing polyphenol oxidase (PPO) activity and altering osmotic regulation in the roots. These effects are expected to aid in the mitigation of cold stress in Lolium perenne. Overall, melatonin treatment would help Lolium perenne to improve growth by promoting AM symbiosis, improving the accumulation of protective molecules, and triggering in antioxidant activity under cold stress.