The yellow stem borer (YSB), Scirpophaga incertulas Walker, is one of the most damaging insect pests of lowland rice in South and Southeast Asia. Breeding for insect resistant has been slow, because the trait is polygenic, no cultivated Oryza sativa line is fully immune, and some chromosomal regions linked to YSB lie next to striped stem borer (SSB) loci on chromosome 4. Classical inheritance studies suggest complementary gene action in donors such as TKM6 and ASD16, and a chromosome-level YSB genome with a recent SSB genome- Unlike earlier surveys that treated evidence from related pests as transferable, this review re-anchors every proposed layer to data from S. incertulas itself, grades each by Technology Readiness Level, and says clearly where evidence has been carried over from other species. The quantitative trait loci on chromosomes 1, 5, 10 and 12 from the donor SM92 are the best-supported YSB loci so far. We set out five genetic layers on a silicon foundation that is agronomic rather than genetic: native loci moved by genomic selection; a Bacillus thuringiensis toxin stack (Cry1Ac, Cry2A, Vip3A) that depends on a high-dose threshold not yet met; the Pin2 protease inhibitor; RNA interference against detoxification and midgut genes, so far tested only by injection; and site-directed editing of OsJAZ10 with tissue-specific control of OsCYP71A1. Whether the resistance lasts will depend on seed-mixture refuges, screening for resistance alleles before release, parasitoid release, and keeping transgenes from spreading to wild Oryza. Reaching a deployable package will take about ten to fifteen years.
The brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae), is one of the most important sucking pests of rice, causing substantial yield losses across the rice-growing region of Southeast Asia. Alternative and sustainable management strategies are therefore essential because its concealed feeding behaviour at the basal portion of the rice plants makes effective management through chemical insecticides challenging. Host plant resistance is one of the most appropriate and eco-friendly approaches for planthopper management. Moreover, the rapid emergence of biotypes, potentially influenced by changing climatic scenarios, necessitates systematic screening of available germplasm to identify new resistance sources for further molecular breeding programmes. In the present study, 63 rice genotypes, comprising 40 advanced breeding lines, 21 popular cultivars/varieties, one resistant check (PTB 33), and one susceptible check (Taichung Native 1), were screened against N. lugens. Among the tested genotypes, four (BRR 2186, Dhobonumberi, PTB 33 and Salkathi) were classified as resistant, eight as moderately resistant, 22 as moderately susceptible, 18 as susceptible, and 11 as highly susceptible. Phenotypic parameters including plant damage, nymphal survival, nymphal developmental period, amount of honeydew excreted, number of feeding marks and weight of female adult hoppers were evaluated to characterise the resistance responses of the genotypes. Significant differences were observed among the tested genotypes/cultivars for all the phenotypic parameters. The resistant genotype BRR 2186 showed the lowest plant damage (6
Soil salinization severely restricts global wheat growth, development, and yield. Exploring salt-tolerant genes from wheat wild relatives is of great significance for salt-tolerant breeding of wheat. In this study, an ethylene response factor gene TtERF1 was cloned from salt-tolerant Tritipyrum “Y1805”. This gene encoded 273 amino acids and contained a typical AP2 domain, belonging to the AP2/ERF family. Under salt stress, TtERF1 was significantly upregulated in Y1805 roots, but undetectable in salt-sensitive common wheat “Chinese Spring”. Using the coleoptile method, TtERF1 was transformed into common wheat. Phenotypic analysis showed that leaf wilting degree and leaf salt injury index were less in the overexpression (OE) line than the wild-type (WT) under salt stress, and survival percentage, root length, plant height, plant fresh weight, and plant dry weight were significantly higher than those of WT plants. Physiological and biochemical measurements revealed that ethylene, soluble sugar, and proline contents, as well as superoxide dismutase, peroxidase, and catalase activities of the OE line were significantly higher than those of WT plants under salt stress; while malondialdehyde content and relative conductivity were significantly lower than for WT plants. In addition, the OE line maintained higher chlorophyll a, chlorophyll b, and carotenoid contents, and the degradation of photosynthetic pigments was slowed under salt stress. However, the TtERF1-silenced plants showed an opposite trend. In summary, TtERF1 OE was associated with increased osmolyte accumulation, antioxidant-enzyme activities, and photosynthetic pigment contents, and contributed to wheat salt tolerance. This study provides an important gene from Tritipyrum to improve wheat salt tolerance.
Reproductive-stage drought is a major constraint to rice productivity, yet its physiological basis across the whole canopy remains poorly understood. The present study elucidates how canopy architecture, leaf-position-specific photosynthetic, non-stomatal and carbohydrate responses contribute to rice tolerance under reproductive-stage drought. Reproductive-stage drought markedly altered leaf functional traits, increasing leaf angle and auricle distance, while reducing leaf area across canopy levels. Genotypes BRR-0054, BRR-0163, and BRR-078 maintained higher leaf area, leaf area index (4.27) and leaf area duration (56.1) indicating superior canopy persistence under stress. Drought reduced net photosynthetic rate by 30–35
Chromium (Cr) is a toxic metal that exerts detrimental effects on plant growth, physiology and yield. The increasing prevalence of Cr contamination necessitates the development of effective mitigation strategies. Salicylic acid (SA), a key signaling molecule and zinc (Zn), an essential micronutrient, are known to enhance crop productivity and stress tolerance. However, their combined role in alleviating Cr toxicity remains unexplored. Therefore, this study aimed to determine the effects of SA and Zn on mitigating Cr-induced stress in barley cultivars. The experiment included two barley cultivars (Sultan-17 and Haider-93) and five treatments: control, Cr stress (40 mg kg⁻¹), Cr + Zn (50 mg kg⁻¹), Cr + SA (1 mM) and Cr + Zn + SA. Chromium stress markedly reduced growth and yield attributes by impairing chlorophyll content, relative water content (RWC) and nutrient uptake, while increasing oxidative damage, Cr accumulation and oxidized glutathione levels. The application of SA and Zn, particularly in combination, significantly mitigated Cr toxicity. The combined treatment considerably improved morphological traits and yield in both Sultan-17 and Haider-93 compared to Cr-stressed plants. These improvements were achieved through increased chlorophyll synthesis, RWC, antioxidant activities, and osmolyte production (including proline, soluble proteins [SP], free amino acids [FAA], glycine betaine [GB], soluble sugars [SS], reducing sugars [RS] and non-reducing sugars [NRS]), as well as enhanced nutrient uptake. Concurrently, the combined treatment reduced Cr accumulation and subsequently decreased electrolyte leakage (EL), malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels. Overall, SA and Zn alleviated Cr toxicity by enhancing antioxidant defense, improving physiological and biochemical functions and restoring yield performance in barley cultivars. These findings highlight the strong potential of SA and Zn as an integrated strategy to alleviate Cr toxicity and improve crop resilience in contaminated environments.
