The C2H2 transcription factor SsZFH1 regulates the size, number and development of apothecia in Sclerotinia sclerotiorum

Sclerotinia sclerotiorum is a notorious phytopathogenic, Ascomycota fungus with a host range of over 600 plant species worldwide. This homothallic, Leotiomycetes species reproduces sexually through a multicellular apothecium which produces and releases ascospores. These ascospores serve as the primary inoculum source for disease initiation in the majority of S. sclerotiorum disease cycles. The regulation of apothecium development for this pathogen and other apothecium-producing fungi remains largely unknown. Here, we report that a C2H2 transcription factor SsZFH1 (zinc finger homologous protein) is necessary for the proper development and maturation of sclerotia and apothecia in S. sclerotiorum and is required for the normal growth rate of hyphae. Furthermore, ΔSszfh1 strains exhibit decreased reactive oxygen species (ROS) accumulation in hyphae, increased melanin deposition and enhanced tolerance to H2O2 in the process of vegetative growth and sclerotia formation. Infection assays on common bean leaves, with thin cuticles, and soybean and tomato leaves, with thick cuticles, suggest that the deletion of Sszfh1 slows the mycelial growth rate, which in turn affect the expansion of leaf lesions. Collectively, our results provide novel insights into the fungal factor mediating maturation of apothecia with additional effects on hyphae and sclerotia development.

Exogenous ABA foliar spray treatment alleviates flooding stress in adzuki bean (Vigna angularis) during the seedling stage

Abscisic acid (ABA) plays an important role in regulating activities of antioxidant enzymes, hormone levels, accumulation of reactive oxygen species under stress. To understand the effects of exogenous ABA treatment on flooding tolerance at seedling stage in adzuki bean (Vigna angularis), the water-sensitive (WS) variety ‘Tianjinhong’ (TJH) and the water-tolerant (WT) variety ‘Longxiaodou 4’ (LXD 4) were foliar sprayed exogenous ABA with 20 μM, followed by flooding stress for 5 days under pot conditions. Our results revealed that under flooding stress at seedling stage, the contents of H2O2 and MDA, proline and soluble protein in adzuki bean leaves significantly increased, the contents of ABA, IAA and SA significantly increased, and the activities of SOD, POD and CAT also significantly increased. Flooding treatment for 5 days resulted in a significant decrease in single pot yield of LXD 4 by 8.40% and TJH by 9.91%. Foliar spray of 20 μM exogenous ABA could resist flooding stress, considerably increased the contents of proline and soluble protein, significantly decreased the contents of H2O2 and MDA, significantly increased the activities of SOD and POD, increased the contents of ABA and SA, and significantly inhibited the increase of IAA content in adzuki bean leaves. Spraying exogenous ABA significantly increased the yield of ‘LXD’ 4 by 6.95% after 4 days of flooding treatment, and ‘TJH’ by 4.46%. To sum up, there were significant differences in physiological stress among different varieties of adzuki bean under flooding stress, and spraying exogenous ABA could effectively alleviate the effects of flooding stress on physiology and yield of adzuki bean. The results of this study provided a theoretical basis for further studying the physiological mechanism of adzuki bean resisting flooding stress at seedling stage and improving the yield of adzuki bean under flooding stress. Thus, foliar spraying exogenous ABA effectively improved submergence tolerance by enhancing the activity of protective enzymes and osmoregulation. These results provided novel insights and were expected to aid in the development of more effective stress resistance cultivation methods in adzuki bean production.

Effect of a low cost diet on the cotton leaf worm, Spodoptera littoralis nucleopolyhedrosis virus pathogenicity and sterile insect technique

Background Mass rearing cost of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is one of the critical methods for the successful utilization of Baculovirus pathogenicity and sterile insect technique (SIT). Effectiveness of both SIT and S. littoralis Nucleopolyhedrosis Virus (SpliNPV) was assessed in response to plant-based diet and substitution of agar with commercial sources of gelling components as feed. Results Pupal and adult recoveries produced by castor bean leaves were significantly high, followed by the agar-based diet. Moreover, larval durations were significantly prolonged for (starch + gelatin)-based diet than the other dietary diets. Obviously, SpliNPV pathogenicity against the larvae reared on (starch + gelatin)-based diet was 2.5 and 2 times higher than those reared on castor leaves and agar-based diet, respectively. Contrary to expectation, the sterility doses of male moths produced by castor leaves and agar-based diet were relatively similar. Conclusion The findings suggest that the lowest cost diets (starch + gelatin)-based diet could be used effectively for increasing the SpliNPV pathogenicity, while either castor leaves or agar-based diet could be considered as a promising choice for SIT program.

Actividad peroxidasa y concentración de proteínas en Phaseolus vulgaris l. tratado con preparaciones homeopáticas

The objective of this work was to evaluate peroxidase activity and protein concentration in the defence system expression of common bean Phaseolus vulgaris L., submitted to different potencies of homeopathic preparations. The treatments were composed by: Arsenicum album, Staphisagria, Silicea and Sulphur, in the 6, 12 and 18 CH potencies, compared to the controls. The bean seeds were sown in pots which were kept in a greenhouse and the treatments were applied to them at 1% in distilled water since the sowing day, with intervals of 15 days until the R7 stage. The first evaluation was performed at 15 e 60 days after sowing, after artificial mechanical damage. Protein concentration and the activity of guaiacol peroxidase (POD) and ascorbate peroxidase (APX) enzymes were determined. Differences between treatments and controls were estimated by Glass Delta effect size analysis. Staphisagria 12CH induced greater increase in protein concentration on bean leaves. The Induction on APX and POD activities were observed in leaves treated with Sulphur in all tested potencies. The Glass Delta effect showed undulatory behaviour, sometimes acting positively, sometimes negatively, throughout all evaluations. Homeopathic preparations have the potential to induce biochemical defence mechanisms in beans, acting as resistance elicitors.

Aktivitas Ekstrak Daun Jarak Kepyar (Ricinus communis Linnaeus) terhadap Perkembangan Nematoda Meloidogyne spp. pada Tanaman Tomat (Lycopersicum esculentum Miller)

Meloidogyne spp. is one of the nematodes that cause root-knot on tomato plants. Thebotanical nematicide that potentially suppresses the nematode is castor bean leaves (Ricinuscommunis Linnaeus) extract. This research aimed to get the lethal concentration (LC50 andLC95) of castor bean leaves extract against nematode larvae in-vitro and their effect on thedevelopment of root-knot nematode (Meloidogyne spp.) in-planta on tomato plant. Theresearch was carried out in Plant Pest and Disease Laboratory and Greenhouse of AgricultureFaculty, Universitas Andalas, using a completely randomized design (CRD) with two stages;in-vitro and in-planta. The research was used the experiment method in-vitro testing consistsof six treatments and five replications, and in-planta testing consists of three treatments andnine replications. The result showed that the application of castor bean leaves extracts invitrocan suppress Meloidogyne spp. larvae with LC50 by 0,27% and LC95 by 0,87%. Theapplication of castor bean leaves extract in-planta with treatment concentration 2xLC95(1,74%) showed effectiveness by 74,69% against the developments of Meloidogyne spp. ontomato plant roots.

Complete Genome Sequence Resource of a Strain of Curtobacterium flaccumfaciens pv. flaccumfaciens, the Causal Agent of Bacterial Wilt of Common Bean, from Turkey

Curtobacterium flaccumfaciens pv. flaccumfaciens is the causal agent of bacterial wilt of common bean (Phaseolus vulgaris), a disease that can reduce yields of this economically important crop worldwide. Current genomics resources for this bacterial pathogen are limited. Therefore, long-read sequencing was used to determine the complete genome sequence of a pathogenic C. flaccumfaciens pv. flaccumfaciens strain isolated from common bean leaves showing irregular necrotic lesions with yellow borders collected in a commercial field in Turkey in 2015.

Antibiotic-induced changes in Tetranychus truncatus bacterial community alter fecundity, longevity and sex-ratio

The bacterial communities of arthropods play important roles in the growth and development of their hosts, such as by providing nutrition or protecting against parasites and pathogens. However, for Tetranychus truncatus, a major crop pest, very little is known about its bacterial community. To understand the effects of the bacterial community on T. truncatus, mites were fed bean leaves that had been soaked in different concentrations of tetracycline hydrochloride (5 mg to 5 g per L). Antibiotic treatment had a negative impact on the fitness of T. truncatus, decreasing their fecundity and longevity. However, we could not exclude the possibility that the decrease in fecundity was due to a toxic effect of the antibiotic. 16S rRNA analyses showed that the antibiotic treatment did not significantly affect the diversity of bacterial species, but it did significantly change their relative abundances. Furthermore, predicted functions of microbiota were also changed with antibiotic treatment. Our research revealed that the antibiotic induced change of bacterial communities mostly decreased the fecundity of T. truncatus, although we couldn’t totally exclude the direct toxin of antibiotics on spider mites.

Effects of Some Plant Extracts, Bioagents, and Organic Compounds on Botrytis and Sclerotinia Molds

<em>Botrytis cinerea</em> and <em>Sclerotinia sclerotiorum</em> are necrotrophic fungi and are closely related pathogenic fungi that infect hundreds of plant species worldwide. In this study, the natural botryticidal/scleroticidal efficacy of some plant extracts, bioagents, and organic compounds known to possess antifungal activity was evaluated. Pathogenicity tests of the fungal molds showed virulence divergence, depending on the isolate and host plant. All <em>B. cinerea</em> isolates, except the BF isolate that infected only broad bean leaves, demonstrated ability to infect detached lettuce and broad bean leaves. Moreover, all <em>Sclerotinia sclerotiorum</em> isolates, except for SSP, demonstrated ability to infect the two plant species, whereas the SSB isolate did not cause any infection in broad bean leaves. The efficacies of <em>Moringa oleifera</em> (Mor), <em>Cinnamomum zeylanicum</em> (Cin), amino acid derivatives (Aad), <em>Trichoderma harzianum</em> (TH), <em>Cactus</em> spp. (Agr), and <em>Bacillus subtilis</em> (BS) were tested either in vitro or in vivo against the highly virulent isolates of the two pathogenic fungi. The efficacy of most potential biofungicides was consistent in vitro as well as in vivo, and the inhibitory efficacy of TH, BS, Cin, Mor, and Aad treatments was significantly high against <em>Botrytis cinerea</em> and <em>Sclerotinia sclerotiorum</em> in vitro and ranged from 62% to 100%, depending on the isolate. In addition, BS, Aad, TH, and Mor treatments had significant inhibitory effects ranging from 53% to 100% against most of the isolates on lettuce leaves. The Agr and Cin treatments exhibited low or no inhibitory effects against many isolates in vivo, and they reduced the mold infection caused by only BCC and SSB isolates. Most of the tested potential biofungicide treatments tended to reduce mold infections, and some of them, such as Cin, exhibited a higher inhibitory effect in vitro than the others. Real-time PCR was conducted for some symptomatic/asymptomatic samples, and the results showed either consistent molecular/symptomatic patterns or latency of <em>B. cinerea</em>. The results confirmed the suitability of the studied natural compounds as effective biofungicides, and they could be the best choice to safely control the most destructive fungal molds.

Nitrogen fertilization management in common bean and castor bean intercropping systems

The objective of this work was to evaluate the nutrition and agronomic characteristics of common bean and castor bean under intercropping subject of nitrogen fertilization in top dressing. A randomized block design in a 2×2×4 + 4 factorial scheme was used, and there were three replicates. The treatments consisted of two common bean cultivars (Pontal and Pérola), which were intercropped with two castor bean cultivars (Energia and Paraguaçu), and combined with four nitrogen treatments (0, 50, 100 and 200 kg ha-1). Four additional treatments involved bean and castor bean cultivars at a single dosage of 40 kg ha-1 nitrogen. The nitrogen, potassium, calcium, magnesium and sulfur contents in castor bean intercropped with common bean leaves were influenced by nitrogen treatments. For common bean applied as top dressing, the maximum grain yields were 1,122 and 1,024 kg ha-1 for cultivars (cvs.) Pontal and Pérola, respectively, with a dose of 100 kg ha-1 nitrogen. Similar results were observed for castor bean, for whom 100 kg ha-1nitrogen provided the largest number of bunches and number of berries per bunch and the highest grain yield. The maximum values observed were 38 and 27 bunches per plant, 27.6 and 35.4 berries per bunch and 1,474 and 1,286 kg ha-1 grain yield for cvs. Paraguaçu and Energia, respectively.