Sugarcane is a water-intensive crop, and optimizing its water use requires understanding physiological responses to water deficit stress. Moisture deficit in leaves reduces the rate of photosynthesis by depleting the efficiency of PSII, measured by chlorophyll fluorescence. This study evaluated the impact of leaf desiccation on PSII sensitivity in sugarcane cultivar Co-86032 using desiccated and non-desiccated treatments. Chlorophyll fluorescence transients were recorded every two hours, and 23 out of 83 transients effectively captured desiccation effects. The polynomial regression analysis conducted for each transient in relation to leaf moisture content revealed for the first time, the threshold tolerance of 23 transients to depleting leaf moisture. A significant 50
Plants commonly face abiotic stressors like drought, salinity, and limited nutrient availability which disrupt the homeostatic networks of mineral acquisition and hamper productivity. In this review we aim to clarify the molecular platforms by which plants sense and act in response to fluctuating availability of nitrogen and phosphorus under stress. Our data show that the dual-affinity nitrate transporter NRT1.1 functions as a sensor and transporter, controlling root architecture and downstream signaling through the TOR-NLP7-SnRK1 pathway to modulate nitrate homeostasis under water and nutrient stress. NRT1.1 activity is also modulated by abscisic acid (ABA) via the PP2C-type phosphatase ABI2, which regulates its phosphorylation status and thereby its nitrate transport capacity. This highlights a direct point of integration between ABA and nitrogen signaling (Leran et al., 2015). Perception of phosphorus is also controlled through the PHR1-SPX module: with Pi availability in excess, SPX proteins suppress PHR1 activity; However, under Pi-deficient conditions, this inhibition is lifted, allowing PHR1 to induce the expression of PHT1 phosphate transporters and miR399, which mediates systemic phosphate remobilization by targeting PHO2 (Puga et al., 2014; Duan et al., 2008). This PHR1-SPX interaction has been experimentally validated using yeast two-hybrid (Y2H) assays, co-immunoprecipitation, and reporter gene analysis, confirming the direct physical interaction under high Pi availability (Puga et al., 2014). Along with nutrient-specific pathways, our data reveal strong interactions between hormonal signaling, reactive oxygen species (ROS), and calcium signaling. Drought-induced ABA accumulation modulates NRT1.1 expression and synchronizes nitrogen uptake with water status; ethylene signaling under low Pi availability enhances root hair growth for acquisition of phosphate; and ROS bursts under nutrient deficiency activate calcium-dependent protein kinases (CDPKs) and MAPKs to modulate transporter stability with precision. Oscillations in calcium, sensed by CBL-CIPK complexes, integrate multiple stress signals further to modulate ion channels (e.g., AKT1 for potassium uptake) and transcriptional networks. Lastly, we describe biotechnological innovations, specifically CRISPR-Cas9 genome editing and nanotechnology-capable of enhancing nutrient-use efficiency and stress tolerance. Targeted editing of OsNPF3.1 and OsHAK8 alleles illustrates how CRISPR can enhance nitrogen and potassium uptake under stressful conditions, while new nanofertilizers (like ZnO and Si nanoparticles) and ROS-scavenging nanomaterials designed for mitigation of oxidative stress provide targeted, slow-release avenues for micronutrient delivery and protection from oxidative damage. They combine to elucidate how NRT1.1 and PHR1-SPX modules, as enhanced by hormone-ROS-Ca²⁺ cross-signaling, regulate stress nutrient acquisition. They also provide the potential to use CRISPR and nanotechnology-based approaches to grow more nutrient-use-efficient and abiotic stress-tolerant plants.
Drought stress induces a range of physiological changes in plants, including oxidative damage. Ascorbic acid (AsA), commonly known as vitamin C, is a vital non-enzymatic antioxidant capable of scavenging reactive oxygen species and modulating key physiological processes in crops under abiotic stresses like drought. Chickpea (Cicer arietinum L.), predominantly cultivated in drought-prone regions, offers an ideal model for studying drought tolerance. We explored the potential of AsA phenotyping to enhance drought tolerance in chickpea. Using an automated phenomics facility to monitor daily soil moisture levels, we developed a protocol to screen chickpea genotypes for endogenous AsA content. The results showed that AsA accumulation peaked at 30% field capacity (FC)—when measured between 11:30 am and 12:00 noon—coinciding with the maximum solar radiation (32 °C). Using this protocol, we screened 104 diverse chickpea genotypes and two control varieties for genetic variability in AsA accumulation under soil moisture depletion, identifying two groups of genotypes with differing AsA levels. Field trials over two consecutive years revealed that genotypes with higher AsA content, such as BDNG-2018-15 and PG-1201-20, exhibited enhanced drought tolerance and minimal reductions in yield compared to standard cultivars. These AsA-rich genotypes hold promise as valuable genetic resources for breeding programs aimed at improving drought tolerance in chickpea.
Soybean stands out with a high protein (35-45 %) and oil content (18-22 %) is one of the important plant-based protein sources. However, the presence of Kunitz Trypsin Inhibitor (KTI), an anti-nutritional factor, reduces the bioavailability of soybean proteins. While thermal inactivation of KTI is possible, it compromises protein solubility and leaves residual activity. Therefore, eliminating KTI through genetic approaches is crucial to improving soybean's nutritional profile. This study aimed to develop soybean genotypes devoid of KTI through marker-assisted selection (MAS) to enhance their nutritional value and global marketability. Hybridization was conducted between recipient parents (AMS-MB-5-18 and AMS-MB-5-19) and donor parents (NRC-101 and NRC-127) to produce four cross combinations. Marker-assisted screening was used to identify plants carrying the null KTI allele across successive backcross generations (BC1F1 to BC1F4). A total of 342 SSR markers were used to assess molecular polymorphism and determine recurrent parent genome content (RPGC) recovery. Absence for KTI peptide was confirmed with native polyacrylamide gel electrophoresis (PAGE). In addition, expression of the KTI3 gene was evaluated during seed developmental stages (R5 and R6) using quantitative PCR. Hybridization efforts yielded 60 F1 seeds with a 12 % success rate. Backcrossing resulted in the production and screening of 259 BC1F2 plants, 45 BC1F3 plants, and 8 BC1F4 plants carrying the null KTI allele. RPGC recovery increased across generations, with BC1F4 plants achieving 84.15 % in Cross A (AMS MB 5-18 X NRC 101) and 83.72 % in Cross B (AMS MB 5-18 X NRC 127). Native PAGE confirmed the absence of KTI peptide in 8 BC1F4 plants. Expression profiling of KTI3 gene via qRT-PCR revealed that expression was significantly higher during the R5 stage compared to R6, with fold changes ranging from 1.39 to 267.64 in R5 and 8.19 to 130.77 in R6. Null parent lines exhibited minimal KTI3 expression, consistent with their genetic background. These findings confirmed the successful introgression of the null KTI allele and its desired effect on trait in advanced backcross populations.
This study investigated the effect of combining full and reduced recommended dose of fertilizer (RDF) levels with Nano Diammonium Phosphate (DAP) on growth, yield, and nutrient dynamics in chickpea (Cicer arietinum). Two-year field experiments was conducted using a randomized block design with 10 treatments and 3 replications. Treatments included the control, 100% RDF, 75% and 50% RDF, and combinations of these with Nano DAP seed treatments and foliar sprays. Key parameters measured included plant growth, yield components, seed and straw yields, nutrient content and uptake, The 100% RDF treatment produced the highest seed yield (15.98 q ha-1), followed by 75% RDF + Nano DAP (13.73 q ha-1). Nano DAP treatments increased yield compared to equivalent RDF levels alone. The 100% RDF treatment also resulted in maximum nutrient content and uptake in seed and straw. While Nano DAP improved nutrient use efficiency compared to conventional fertilizers, it did not match the performance of 100% RDF when combined with reduced fertilizer levels. The study demonstrated Nano DAP can partially substitute for conventional fertilizers in chickpea, but cannot fully replace RDF for achieving maximum productivity and nutrient uptake.
