Annals of Applied Biology最新文献

Seed germination testing is an important aspect to assess the quality of seed. Response to germination is a complex phenomenon governed by genetic and physio-biochemical factors and environmental factors such as temperature, water potential and so forth. The germination time course is modelled with temperature as a covariate when imbibed under saturated conditions by using the thermal time property of seeds. However, the thermal time model does not account for a threshold effect of water potential in the situation of incomplete germination. Therefore, properties of the three-parameter log-logistic distribution have been explored theoretically to satisfy hydro time properties of seed germination when modelling this process. The parameters could differentiate the effects of biological factors on seed germination, which will help the investigation of rice seed viability in various climatic conditions. A novel methodology has been developed for efficient estimation of parameters that accounts for correlation and heteroscedastic error variance. The performance of the estimation methods, along with the maximum likelihood estimation method, has been studied. Finally, the impact of plant growth and seed maturity conditions in the mother plant upon seed germination has been investigated theoretically. Unlike the estimation of only cardinal temperature which does not account for a threshold effect of water potential, favourable temperatures for rice varieties of various maturity groups germinated under different water stress conditions have been recommended in the current research.

Brown planthopper, Nilaparvata lugens (Stål) is a major rice pest, with infestations increasing in India in recent decades. While various control methods exist, deploying resistant rice varieties is economical. Among the four known N. lugens biotypes in the world, biotype-4 predominates in India, overcoming plant resistance through biochemical and molecular adaptations. Molecular markers, particularly DNA-based markers, were employed to characterise resistance-associated loci, enabling precise screening and selection of resistant genotypes. Hence, in this study, 22 previously reported resistant rice germplasms carrying different resistant QTLs/genes, along with resistant check (Salkathi), susceptible check (TN-1) and four popular varieties, were used for both phenotypic and genotypic studies. A phenotypic screening over three years identified two highly resistant genotypes (Dhobanumberi & Salkathi with score 1) and eight resistant genotypes (score 3). Additionally, resistance genotypes exhibited lower plant damage (4%–23%), reduced honeydew excretion (4.8%–6.5%), lower nymphal survival (29%–47%) and delayed wilting (18–23 days) compared to susceptible genotypes. Genetic analysis revealed an average genetic diversity of 0.269 and a polymorphism information content of 0.228 across 89 markers linked to 31 resistance QTLs/genes. Cluster and population structure analyses grouped the genotypes into three primary genetic clusters, which were further validated by principal coordinate analysis, distinguishing susceptible, moderately resistant, and resistant genotypes. Genetic variation analysis indicated that 92% of the variation was within the population, while 8% was among the populations. Marker-trait association analysis using generalised linear models (GLM) and mixed-linear models (MLM) identified five significant markers associated with N. lugens resistance, viz. RM261 (Bph15), RM1305 (Bph12), RM6843 (Qbph2), RM6869 (Bph2) and RM16853 (Bph27). Among them, RM261 (Bph15) was found significantly associated (p < .05) with N. lugens resistance in both GLM and MLM approaches. These identified resistant sources and genes against BPH biotype-4 would be useful for the development of durable resistant varieties against N. lugens.

The use of well-feathered nursery trees considerably enhances precocity and, consequently, the profitability of apple orchards. This study aimed to develop an efficient technique for feather development in 1-year-old apple nursery trees of ‘Gala Mast’ and ‘Oregon Spur’ grafted on MM.106 rootstock by employing benzyladenine (BA). The concentration, spray frequency, and spray interval of BA had a statistically significant impact on tree quality, with the spray interval being the most influential factor. An increase in concentration from 500 to 600 ppm positively affected most of the studied variables. However, the values for these variables decreased with further increasing concentration from 600 to 700 ppm. In ‘Gala Mast’, the greatest positive effect on most of the tree quality determinants was observed with four sprays, and increasing the spray frequency from four to five did not further affect the number of feathers, feathers with the optimum length, and feathering zone. Conversely, an increase in spray frequency from three to five led to a positive response in ‘Oregon Spur’ nursery trees quality in terms of number of feathers, total feather length, and feathering zone. However, statistically significant differences in the number of feathers and feathering zone were not found with four and five sprays. Further, a 1-week spray interval was found most effective for ‘Gala Mast’, whereas a 2-week interval was optimal for ‘Oregon Spur’. In conclusion, applying four sprays of 600 ppm BA at 1-week intervals for ‘Gala Mast’ and 2-week intervals for ‘Oregon Spur’ resulted in the most favourable effects on the number of feathers and overall quality of the nursery trees. The findings of this study indicated that the frequency of BA sprays depends on the growing period length, while the interval between applications is determined by the cultivar's ability to resume terminal growth after temporary suppression by BA.

The rice transcription factor OsBZ8 binds to the core sequence ACGT in a G-box (CACGTG), hybrid G/C-box (GACGTG) or abscisic acid response element (ACGTGGC) in the upstream promoter of its target genes. The expression of this transcription factor is largely restricted to seeds 25 days after pollination, coinciding with isoprenoid accumulation, suggesting it may be responsible for the coordinated regulation of the mevalonate (MVA) and the methylerythritol 4-phosphate (MEP) pathway genes. We therefore screened the corresponding promoters for relevant cis-acting elements in 14 genes (three isoforms each of AACT, HMGS, HMGR and DXS and two of IPPI) involved in the MVA/MEP pathways and found a G-box or hybrid G/C-box motif within the first 300 bp upstream of five genes (OsAACT3, OsHMGS1, OsHMGR1, OsDXS2 and OsIPPI1). The expression profile of all five genes in rice seeds matched that of OsBZ8, with stronger expression in the embryo than the endosperm. The specific binding of OsBZ8 to three of the promoter elements was confirmed in yeast one-hybrid assays, and reporter gene constructs provided direct evidence of transactivation in a representative gene. Our findings provide insight into the regulation of isoprenoid metabolism in rice and will facilitate the use of transcription factors in rice seeds to boost the production of target metabolites.

Plant essential oils (EOs) represent a potentially effective, safe, and eco-friendly alternative to synthetic pesticides that cause negative effects for human health and the environment. While numerous studies have been conducted with EOs from tropical and temperate plants, very few studies have investigated the toxicity of EOs from Nordic plants against plant pathogenic organisms and pests. The present study evaluated in airtight glass chambers the toxicity of vapours produced by EOs obtained from sweet gale, balsam poplar, Labrador tea, jack pine, and black spruce against different pathogenic organisms and pests of cultivated plants. Vapours of Labrador tea EO strongly or completely inhibited the mycelial growth of Alternaria solani, Phytophthora capsici, and Sclerotinia sclerotiorum, while vapours of sweet gale, black spruce, and jack pine EOs inhibited the mycelial growth to a lesser extent. Vapours of all tested EOs were shown to have bactericidal activity against Clavibacter michiganensis subsp. michiganensis, insecticidal activity against bird cherry-oat aphids, acaricidal activity against spider mites, and phytotoxicity against Powell's amaranth. The study reveals the toxicity of EOs from Nordic plants against various pathogens and pests affecting crops, opening new avenues of research for the development of low-risk alternatives to synthetic pesticides in agriculture, with minimal impact on the environment and human health.

Specific binding sites for non-circulative viruses within the mouthparts of aphid vectors have been investigated with limited success. Such sites have been described more precisely for cauliflower mosaic virus (CaMV, Caulimovirus), and shown to be restricted to the acrostyle, a specific anatomical structure located in the common duct of the aphid stylets. However, the nature and precise location of binding sites of other non-circulative viruses (e.g., cucumoviruses and potyviruses), and whether distinct viral species compete for the same sites remains unknown. In this study, competition between non-circulative viruses for binding sites was assessed for viruses that differ in their transmission mode: cucumber mosaic virus (CMV, Cucumovirus), transmitted by the capsid strategy, and three viruses using the helper strategy for their transmission—turnip mosaic virus (TuMV, Potyvirus), zucchini yellow mosaic virus (ZYMV, Potyvirus), and CaMV. In this work, we performed competition and sequential acquisition experiments, with contrasting results obtained depending on the virus species used and the sequence of acquisition/inoculation of the potentially competing viruses. Our results showed that potyviruses and caulimoviruses do not appear to compete for the same binding sites and/or receptors within aphid stylets, as no modifications in their transmission rates were observed regardless of their acquisition sequence. However, a decrease of CMV transmission rate when ZYMV was previously acquired, suggests that potyviruses and cucumoviruses might compete for binding sites in their aphid vectors. Moreover, we observed that potyviruses and cucumoviruses can be co-acquired and co-inoculated in the same plant cell during a single intracellular puncture, demonstrating co-infection of individual cells by more than a single virus species.

Tomato leaf curl New Delhi virus (ToLCNDV) causes significant yield and fruit quality losses in cucurbit crops, particularly in the Mediterranean region. Sources of resistance to ToLCNDV have been identified in various cucurbits, including cucumber, where quantitative trait loci (QTLs) have been mapped to chromosomes 1, 2, and 6. A candidate gene encoding RNA-dependent RNA polymerase 3 (CsRDR3) has been identified and functionally validated in QTL1, and a candidate gene encoding heat shock factor A2 (CsHSFA2) has been identified in QTL2. We performed a field screening of cucumber accessions and identified ABS.PE.045 as potentially resistant to ToLCNDV. Since prototype Mediterranean isolates (ToLCNDV-ES) induce only mild symptoms in cucumber, we cloned ToLCNDV-CsES, an aggressive isolate from cucumber. The proteins from ToLCNDV-ES and ToLCNDV-CsES differ by only 10 amino acids; however, ToLCNDV-CsES induces severe symptoms in cucumber plants of the Wisconsin cultivar. We used ToLCNDV-CsES to phenotype ABS.PE.045, Wisconsin, and their F₁ and F_2,3 progenies. ABS.PE.045 plants were highly resistant, F₁ plants showed symptoms and virus progression similar to those of Wisconsin plants, and F₂ individuals segregated, suggesting the involvement of two or more genes in resistance determination. A bulk segregant analysis coupled with RNA-Seq suggested the involvement of four QTLs in resistance, with defined intervals on cucumber chromosomes 1, 2, 6, and 7. Our analysis suggested that CsRDR3 and CsHSF2A are bona fide candidates for QTLs 1 and 2, in agreement with previous studies. We propose CsaV3_7G022160, annotated as encoding a CCCH zinc finger protein, as a candidate for QTL7. The new marker and cloned ToLCNDV-CsES represent important tools for breeding resistance to this virus in cucumber.

Potato (Solanum tuberosum L.), a cornerstone of global food security, is valued for its nutritional value and diverse uses but faces significant production problems caused by plant-parasitic nematodes, particularly potato cyst nematodes (Globodera rostochiensis and G. pallida) and root-knot nematodes (Meloidogyne spp.). These pests cause significant yield and economic losses worldwide, worsened by the persistence of nematode cysts in the soil and the limited use of chemical nematicides due to environmental concerns. This review focuses on nematode biology, their impact on potato production, and various control strategies. It highlights the transformative potential of CRISPR/Cas-based genome editing for the development of nematode-resistant potato varieties through precision genetic modifications, as well as resistance traditionally established by transferring resistance genes. Successful applications of CRISPR/Cas in potato, including targeting susceptibility genes such as StDND1 and StDMR6-1 for disease resistance, demonstrate its efficacy, although nematode-specific applications remain under-explored. Challenges in genome editing with CRISPR/Cas9, such as polyploidy, off-target effects, and problems in the gene delivery system, have been addressed. Future perspectives are discussed, emphasizing the need for strategic advancements in CRISPR-based approaches to develop superior cultivars with durable, broad-spectrum resistance to agricultural stressors.

Interactions between environmental factors are a major source of ecosystem complexity. Here we re-analyse published data to define the type of relationships between drought and biotic and abiotic factors affecting plants and aphids from molecular to community scales. Out of 329 pair-wise relationships, 55% were additive, 36% antagonistic and 9% synergistic. The type of relationship varied with plant and aphid trait; plant and aphid genotype; timing, duration and intensity of stress in relation to plant and aphid developmental stage; intra- and inter-specific competition; and relations at higher trophic levels. We identify two aspects to make future research in this field more effective. First, frameworks are needed to scale from molecular cross-talk between stresses to the relevant traits: crop yield in agriculture and fitness in nature. Second, experiments require a shift from a nominal (e.g., well-watered, droughted) to a quantitative characterisation of stress, and realistic conditions to avoid artefacts from over-simplified settings, for example, roots confined to pots, insects confined to cages. In the absence of predictive frameworks, interventions in agriculture and conservation are needed that are robust to the uncertainty in the type of relationship, that is, antagonistic, additive or synergistic.

Various genetic and environmental factors influence plant reproductive success, manifesting at different growth stages, fertilisation and germination. Fennel (Foeniculum vulgare Mill.) is a perennial plant with significant medicinal and nutritional value; however, limited information regarding its reproductive success has been reported in various studies. This research investigated the reproductive processes of fennel in 12 genotypes and three planting ages (1-, 2- and 3-year-old) over two agronomic years (2020 and 2021) in Pakdasht, Iran. Traits related to reproduction were evaluated, including the seed-to-ovule ratio (S/O), fruit-to-flower ratio (F/F), seed yield and germination at different temperatures. The results indicated that the highest number of surviving plants was observed in 1-year-old genotypes, while the highest seed yield was recorded in 2-year-old plants (in 2020) and 3-year-old plants (in 2021). The S/O and F/F ratios varied between 0.23 and 0.77 and 0.23 and 0.88, respectively. The highest germination percentage was recorded in 1-year-old plants at 10°C. Genotypes with a higher number of inflorescences and an S/O ratio close to 1 are suitable options for improving yield. Considering the slow growth of fennel in the first year and the impact of temperature on germination, appropriate planting timing and utilising winter colds are effective in optimising germination and seedling establishment. This research provides insights into the reproductive processes of fennel and offers strategies for improving yield by selecting suitable genotypes and adopting optimal cultivation practices.