Plant growth-promoting rhizobacteria (PGPR) enhance rice productivity by boosting nutrient uptake and hormone production and pathogen suppression. However, identifying efficient and multifunctional PGPR strains adapted to specific rice-growing environments remains challenging. This study aimed to isolate and assess efficient rice rhizosphere PGPR from the rice rhizosphere for their growth-promoting potential under controlled conditions. Eighteen bacterial isolates were initially screened for key PGPR traits, including phosphate (P) and zinc (Zn) solubilization, indole acetic acid (IAA) production, potash (K) mobilization, and antagonistic activity. Based on superior performance, two isolates were identified as Acinetobacter junii SK13 (AJNAU-SK13) and Providencia vermicola SK16 (PVNAU-SK16). Their efficacy was evaluated under greenhouse conditions using individual (T1: AJNAU-SK13, T2: PVNAU-SK16) and combined (T3: AJNAU-SK13 + PVNAU-SK16) inoculations. All treatments significantly improved root and shoot growth, biomass, chlorophyll content, enzyme activities (protease, and amylase), and total soluble sugars (TSS) at 10 and 20 days after treatment (DAT). Notably, T2 increased root growth (150
Amaranthus is a major leafy vegetable, and India is centre of its diversity. To assess variation within the Indian germplasm, 96 Amaranthus genotypes were evaluated using an augmented block design, scoring 20 morphological descriptors and analyzing DNA-based diversity with inter-simple sequence repeat (ISSR) and simple sequence repeat (SSR) markers. All morphological traits showed a wide range of variation, including rare or unique phenotypes such as novel leaf shapes, white and pink stems, petiole pigmentation, and distinct inflorescence colour patterns. Shannon-Weaver indices ranged from 0.00 to 1.48, with 11 traits showing significant morphological variation. Molecular analyses revealed considerable polymorphism, with six of thirteen ISSR markers and nine of twenty-two SSR markers being polymorphic. Analysis of genetic diversity showed low within-population diversity (Hs = 0.15) but higher total diversity across populations (Ht = 0.26), along with moderate-to-high differentiation (Gst = 0.42) and low gene flow (Nm = 0.34), indicating strong population structuring. Principal coordinate analysis revealed substantial genetic variation, partial population clustering, and evidence of admixture, while marker-based clustering divided the collection into five clusters. Population structure analysis further identified four admixed subpopulations, highlighting the complex genetic relationships within the germplasm. These findings demonstrate structured and exploitable variation in Indian Amaranthus, providing a basis for selecting diverse parental lines, broadening the genetic base through compatible crosses, and supporting crop improvement programs.
Entomopathogenic nematodes (EPNs) are important biological agents used to control various insect pests and can be applied in conjunction with different insecticides. Thus, the objective of this work was to evaluate the survival of infective juveniles (IJs) of two EPN species, Heterorhabditis indica and Steinernema carpocapsae, after exposure to fipronil and imidacloprid. The combination of these nematodes and insecticides at different rates for controlling the white grub Holotrichia serrata was evaluated both in the laboratory and in sugarcane fields. In laboratory assays, two insecticides, fipronil and imidacloprid, at different concentrations had no effect or a negligible effect on the survival of both nematode species, with mortality rates below 4.0 %. The combinations had a synergistic or additive effect on the third-instar grubs of H. serrata and caused faster and greater mortality than either an EPN species or an insecticide alone. Mortality and speed of kill were significantly increased in the combinations of H. indica-fipronil, H. indica-imidacloprid, and S. carpocapsae-imidacloprid, but nematode reproduction was also unaffected by these insecticides. However, both in the laboratory and in sugarcane fields, the degree of interaction varies with nematode species, being synergistic for H. indica-fipronil, H. indica-imidacloprid, and S. carpocapsae-imidacloprid against grubs. These three nematode-insecticide combinations produced significantly (P < 0.05) greater percentage reductions in Holotrichia serrata than did the chlorpyrifos treatment. We conclude that H. indica at 6.1 x 10(8) IJ ha(-1) combined with imidacloprid or fipronil is a practical strategy for the management of H. serrata in sugarcane production
Powdery mildew disease caused by Erysiphe spp inflicts heavy losses in pea crop worldwide. A recessive powdery mildew resistance gene er2 present in pea genotype JI2480 provides a broad-spectrum protection against powdery mildew disease in peas. In the present study, we targeted pea genome sequences around a previously known dominant Sequence Characterized Amplified Region (SCAR) marker ScX17_1400 for developing co-dominant markers for utilization in marker-assisted selection of the er2 gene. Of the ten STS markers developed from the target region, four were effectively converted into Cleaved Amplified Polymorphic Sequence (CAPS) markers. These polymorphic CAPS markers and two LG3-specific SSR markers, AA278 and AA5, exhibited close linkage to er2 when tested on a BC7F2 population derived from a cross between the susceptible genotype Azad P-1 and JI2480. The linkage map of the er2 locus spanned a 5.9 cM region wherein AA278 was most closely linked to er2 at a distance of 1.8 cM. Three cosegregating markers, PsLG3_CAPS-1, PsLG3_CAPS-3, and PsLG3_CAPS-4, were positioned at a distance of 3.2 cM from the gene. When tested across a panel of 28 commercial pea genotypes, the different markers differentiated 6 to 22 commercial pea varieties from er2 donor line JI2480. These markers collectively distinguished 26 commercial pea varieties from JI2480, thereby suggesting their utility for marker-assisted selection of the er2 gene in crosses with these genotypes serving as recipient or recurrent parents. As these markers also differentiated a significant number of commercial pea varieties believed to possess the er1 gene from the er2 donor line JI2480, they can also be effectively utilized to integrate both resistance genes (er1 and er2) in these genetic backgrounds for achieving a broad spectrum and durable resistance against powdery mildews.
The plant growth in potato largely depends on the availability of nutrients in the soil and related genomics of the plant. The present study aimed at unravelling the genomics of potato plant under nitrogen stress conditions. The study identifies and characterizes differentially expressed long non-coding RNAs (DE-lncRNAs), differentially expressed circular RNAs (DE-circRNAs) and alternative splicing (AS) events from shoot, root and stolon tissues of potato varietie Kufri Gaurav, under high and low regimes of nitrogen stress conditions and their roles in regulating genes associated with nitrogen use efficiency (NUE), growth-development and yield. A total of 269 DE-lncRNAs, 26 DE-circRNAs and 20,625 AS genes were identified from in silico studies. A few DE-lncRNAs were found targeting the nitrogen related genes such as L-asparaginase, ubiquitin fold modifier, while rest were involved in metabolic pathways and biosynthesis of secondary metabolites. A total of 12 DE-lncRNAs were validated by real-time qPCR and found to be involved in metabolic processes such as tuber formation, growth development, lipid homoeostasis, nitrogen-relocation. The competing endogenous RNAs (ceRNAs) acting as sponges for miRNAs were studied from interaction point of view. It was observed that 42 and 31 miRNA response elements (MREs) were present on DE-circRNAs and DE-lncRNAs respectively. Interestingly, five miRNAs involved in protein transport, iron homeostasis, adaptive growth etc. were predicted as absorbed by DE-lncRNA and DE-circRNAs simultaneously. The internal ribosomal entry sites (IRES) and AS genes regulating the nitrogen like mandelonitrile lyase, nitrate transporter, and carbon–nitrogen hydrolase were identified as likely contributors to crop nitrogen use efficiency (NUE) and yield. A user-friendly information system based on the findings was developed and made available at https://potatotransdb.rf.gd/ for potato breeders and geneticists. Our findings may help to understand the role of regulatory elements under nitrogen stress in potato and achieve the targets of improving agronomic traits through marker assisted breeding.
