Nitrogen deficiency is a key constraint on crop yield. Cassava, the world’s sixth-largest food crop and a crucial source of feed and industrial materials, can thrive in marginal soils, yet its yield is still significantly affected by limited nitrogen availability. Investigating cassava’s response mechanisms to nitrogen scarcity is therefore essential for advancing molecular breeding and identifying nitrogen-efficient varieties. This research undertook a comprehensive analysis of cassava seedlings’ physiological, gene expression, and metabolite responses under low nitrogen stress. Findings revealed that nitrogen deficiency drastically suppressed seedling growth, significantly reduced nitrate and ammonium transport to aerial parts, and led to a marked increase in carbohydrate, reactive oxygen species, and ammonium ion levels in the leaves. Transcriptomic and metabolomic analyses further demonstrated notable alterations in genes and metabolites linked to carbon and nitrogen metabolism, flavonoid biosynthesis, and the purine metabolic pathway. Additionally, several transcription factors associated with cassava flavonoid biosynthesis under nitrogen-deficient conditions were identified. Overall, this study offers fresh insights and valuable genetic resources for unraveling cassava’s adaptive mechanisms to nitrogen deprivation.

Abiotic stress represents a significant and increasing challenge to global crop productivity and food security. Calcium (Ca ²⁺ ) signaling, initiated by specific “Ca ²⁺ signatures” and interpreted by sensor proteins such as calcium-dependent protein kinases (CDPKs/CPKs) and the CBL-CIPK network, functions as a key regulator of plant adaptive responses. However, contemporary elite cultivars exhibit a reduced genetic base, having forfeited numerous resilient alleles present in wild relatives and landraces during intensive, yield-focused breeding. This review synthesizes evidence demonstrating that natural genetic variation within these calcium sensor genes significantly influences key agronomic traits, including ion homeostasis, stomatal regulation, and water-use efficiency. We then evaluate the effectiveness of integrated genomic approaches, such as pan-genomics, genome-wide association studies (GWAS), and CRISPR-Cas9 genome editing, for systematically identifying and validating these beneficial alleles. Finally, we propose a translational roadmap for the targeted introgression of enhanced calcium sensor variants into modern germplasm. This work provides a strategic framework for developing a new generation of climate-resilient crops, offering a pathway to safeguard global food systems against increasingly erratic environmental conditions.

Background: Xyloglucan endotransglucosylase/hydrolase (XTH) acts as a key cell wall-modifying enzyme and contributes to plant stress resilience. This study aimed to identify the MeXTH gene family in cassava and characterize its potential functions in abiotic stress adaptation. Method: A full set of bioinformatic analyses was performed, including phylogeny, gene structure, conserved motifs, chromosomal localization, synteny, promoter cis-elements and subcellular localization. Expression patterns were examined by quantitative real-time PCR (qRT-PCR). Results: Forty-two MeXTH genes were identified and distributed on 14 chromosomes, encoding proteins with conserved Glyco_hydro_16 (Glycoside hydrolase family 16) and XET_C (Xyloglucan endotransglycosylase C-terminal domain) domains. Genes were clustered into four subfamilies with similar structures. Synteny was closer between cassava and dicots than monocots. Twenty-four stress-, hormone- and light-related cis-elements were detected. Ten MeXTH genes showed obvious differential expression under stress, and most proteins were located in the cell wall. Conclusions: The MeXTH gene family is structurally conserved and can serve as a readout of abiotic stress in cassava. These results provide a theoretical basis for molecular breeding aimed at enhancing stress resistance in cassava.

The selection and breeding of salt-tolerant rice and the use of saline–alkali land for rice cultivation are crucial for food security. However, most studies have focused only on the seedling salt tolerance stage, with little research on the salt tolerance mechanisms during the reproductive growth period. This study selected the salt-tolerant rice line SR17, the salt-tolerant variety SR86, and the salt-sensitive variety IR29 as research subjects. Two salt stress gradients of 0% and 0.5% (7.8 dS m⁻¹) were established. Salt stress was applied continuously from rice transplanting to the maturity stage, and the differences in response mechanisms during the young panicle stage under long-term salt stress were analyzed. The results showed that, under salt stress, SR17 exhibited the least lipid peroxidation and membrane damage, followed by SR86, while IR29 suffered the most severe damage. SR17 and SR86 could reduce oxidative damage and maintain membrane system integrity by activating the antioxidant enzyme system and accumulating soluble proteins. In contrast, the antioxidant system in IR29 was insufficiently activated; this indicates that the adaptability of this variety to salt-induced oxidative stress is relatively poor. The chlorophyll content and most photosynthetic parameters in SR17 showed no significant changes, and leaf gas exchange performance and chlorophyll status were the least affected, whereas IR29 suffered severe damage. Agronomic trait investigation revealed that, compared with the control, SR17 exhibited the smallest reductions in plant height, spikelets per panicle, 1000-grain weight, grain yield per plant, and main spikelet number under salt stress, and the decreases in key yield-related indicators—effective panicle number, grain yield per plant, and seed setting rate—were not significant. This study confirms that SR17 possesses superior salt tolerance and holds potential for further breeding and multi-environment trials, while also providing an important basis for elucidating the physiological mechanisms of salt tolerance during the reproductive stage of rice.