Kaolin Particle Film Protects Grapevine cv. Cabernet Sauvignon Against Downy Mildew by Forming Particle Film at the Leaf Surface, Directly Acting on Sporangia and Inducing the Defense of the Plant

Downy mildew is a major threat to viticulture, leading to severe yield loss. The use of traditional copper-based fungicides is effective, but has adverse effects on the environment and human health, making it urgent to develop an environmentally friendly disease management program. Multi-functional kaolin particle film (KPF) is promising as an effective and safer treatment strategy, since this material lacks chemically active ingredients. In this study, ability of Kaolin particle film (KPF) pretreatment to protect grapevine leaves from Plasmopara viticola was tested and the mode of action of KPF was analyzed. KPF application reduced the disease severity and the development of intercellular hyphae. Additionally, there was reduced accumulation of H2O2 and malondialdehyde (MDA) with pretreatment. The observation of ultrastructure on the leaf surface showed KPF deposition and stomatal obstruction, indicating that KPF protected plants against disease by preventing the adhesion of pathogens to the leaf surface and blocking invasion through the stomata. KPF pretreatment also activated host defense responses, as evidenced by increased activities of anti-oxidative enzymes [superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)] and defense-related enzymes [phenylalanine ammonia-lyase (PAL), chitinases, and β-1,3-glucanases], increased phytohormone signals [abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA)] and the up-regulation of defense genes related to plant defense. Overall, these results demonstrate that KPF treatment counters grapevine downy mildew by protecting leaves and enhancing plant defense responses.

Development and Evaluation of Stable Sugarcane Mosaic Virus Mild Mutants for Cross-Protection Against Infection by Severe Strain

Sugarcane mosaic virus (SCMV; genus Potyvirus) induces maize dwarf mosaic disease that has caused serious yield losses of maize in China. Cross-protection is one of the efficient strategies to fight against severe virus strains. Although many mild strains have been identified, the spontaneous mutation is one of the challenging problems affecting their application in cross-protection. In this study, we found that the substitution of cysteine (C) at positions 57 or 60 in the zinc finger-like motif of HC-Pro with alanine (A; C57A or C60A) significantly reduced its RNA silencing suppression activity and SCMV virulence. To reduce the risk of mild strains mutating to virulent ones by reverse or complementary mutations, we obtained attenuated SCMV mutants with double-mutations in the zinc finger-like and FRNK motifs of HC-Pro and evaluated their potential application in cross-protection. The results showed that the maize plants infected with FKNK/C60A double-mutant showed symptomless until 95 days post-inoculation and FKNK/C60A cross-protected plants displayed high resistance to severe SCMV strain. This study provides theoretical and material bases for the control of SCMV through cross-protection.

Diversity of undergrowth understorey in Sibolangit Nature Park, Deli Serdang Regency, North Sumatra, Indonesia

The Sibolangit Nature Park area is one of the Nature Parks in North Sumatra which has various types of diverse plants ranging from understorey, epiphytes and various endemic tree species. The purpose of this study was to see the diversity of understorey species found in the Sibolangit Nature Park and its benefits. The results showed that there were 27 types of understorey plants from 18 families. Based on the family, the most commonly found were the Araceae family, namely 6 species (22.22%) and Zingiberaceae (11.11%). The understorey has the potential for medicinal plants, ornamental plants, poisonous plants, etc. The results showed that there were 15 species (55.5%) which were included in the category of ornamental plants, 7 species (25.92%) were included in medicinal plants, 1 species of poisonous plants (3.70%), 1 species of spice plants (3,70%), and 1 species (3.70%) protected plants and 2 species (7.40%) could not be explained scientifically. A protected and endangered plant species is Amorphophallus titanum

Inventory of vascular spore plants and gymnosperms of the Kabardino-Balkar State Highland Reserve

The Kabardino-Balkar State Highland Reserve (KBGWZ) was established in 1976 to protect the alpinefloristic and faunal complexes of the Central Caucasus. The flora of the reserve includes about 1000 species of vascularplants. The inventory showed the presence in its flora of 40 species of vascular spore plants belonging to the divisionsLycopodiophyta (5 species, 2 families), Polypodiophyta (35 species, 12 families). Gymnosperms are represented by thedivisions Pinophyta, containing 3 families and 7 taxa of the species rank and below, as well as the division Gnetophytawith one representative of the genus Ephedra. Among the protected plants in the Red Book of the Russian Federation(2008), Taxus baccata is included. Asplenium scolopendrium (sub nom. Phyllitis scolopendrium), Ceterach officinarum andPolystichum lonchitis are in the Red Data Book of Kabardino-Balkar (2018). Among gymnosperms, Abies nordmannianaand Picea orientalis are also regionally protected species.

Markets Survey On Traditional Medicine of Lijiang City, Yunnan Province, China

Background: Traditional markets are important trading places for medicinal plants, and market surveys often engage in ethnobotanical research to record the herbal plants used locally and related traditional knowledge. However, information on the market traded medicinal plants is not well documented from traditional markets in Lijiang City, Yunnan. This research is an ethnobotanical survey focusing on medicinal plants traded in traditional markets of Lijiang City, and contributes to the understanding of medicinal plants and related information used by the Naxi people.Methods: Ethnobotanical surveys were carried out during two years (2019-2020). Three traditional markets in Lijiang City were investigated. The methods we used include literature research, participatory surveys, key insider interviews and group discussions.Results: As a result, 318 medicinal plants were recorded including 29 unidentified medicines. The plant medicines were from medicinal plants of 97 families belonged to Angiosperm, Gymnospermae, Pteridophyta, Bryophyta, Lichenes and Fungi. Asteraceae provided the maximum numbers of medicinal plants. Among them, there were 258 species (89.27%) of wild plants, 15 species (5.19%) were cultivated, and 16 species (5.54%) were wild or cultivated. There were 22 species of national protected plants in China, including 3 species of national first-level protected plants and 19 species of national second-level protected plants. Among the recorded diseases, 58.13% of medicinal plants are used to treat musculoskeletal system and connective tissue diseases and digestive system diseases. A total of 31 kinds of medicinal plants can be found in Dongba Sutra or Yu Long Ben Cao.Conclusion: This study surveyed herbal medicine in the market of Lijiang City, analyzing and revealing resource compositions and current market situations. The medicinal plants used by the Naxi people are diverse and are used to treat a wide spectrum of body disorders. There are many wild medicinal plants, and in order to ensure sustainable development, its natural protection should be strengthened. Knowledge of medicinal plants recorded in Naxi medical classics has ethnobotanical value and should be further developed.

Oxylipins From Different Pathways Trigger Mitochondrial Stress Signaling Through Respiratory Complex III

Plant oxylipins are signaling molecules produced from fatty acids by oxidative pathways, mainly initiated by 9- and 13-lipoxygenases (9-LOX and 13-LOX), alpha-dioxygenases or non-enzymatic oxidation. Oxylipins from the 9-LOX pathway induce oxidative stress and control root development and plant defense. These activities have been associated with mitochondrial processes, but precise cellular targets and pathways remain unknown. In order to study oxylipin signaling, we previously generated a collection of Arabidopsis thaliana mutants that were insensitive to the 9-LOX products 9(S)-hydroxy-10,12, 15-octadecatrienoic acid (9-HOT) and its ketone derivative 9-KOT (noxy mutants). Here, we describe noxy1, noxy3, noxy5, noxy23, and noxy54 mutants, all affected in nucleus-encoded mitochondrial proteins, and use them to study the role of mitochondria in oxylipin signaling. Functional and phenotypic analyses showed that noxy plants displayed mitochondrial aggregation, reduced respiration rates and resistance to the complex III inhibitor Antimycin A (AA), thus indicating a close similarity of the oxylipin signaling and mitochondrial stress. Application of 9-HOT and 9-KOT protected plants against subsequent mitochondrial stress, whereas they boosted root growth reduction when applied in combination with complex III inhibitors but did not with inhibitors of other respiratory complexes. A similar effect was caused by linear-chain oxylipins from 13-LOX or non-enzymatic pathways having α,β-unsaturated hydroxyl or keto groups in their structure. Studies to investigate 9-HOT and 9-KOT activity indicated that they do not reduce respiration rates, but their action is primarily associated with enhanced ROS responses. This was supported by the results showing that 9-HOT or 9-KOT combined with AA amplified the expression of oxylipin- and ROS-responding genes but not of the AA marker AOX1a, thus implying the activation of a specific mitochondria retrograde signaling pathway. Our results implicate mitochondrial complex III as a hub in the signaling activity of multiple oxylipin pathways and point at downstream ROS responses as components of oxylipin function.

Bagging of bunches and protected production in ‘Niagara Rosada’ vineyard

Vineyards of ‘Niagara Rosada’ have shown great productive potential. However, the grape production has been affected by factors related to climate adversities. Thus, this study aimed to evaluate the effect of plastic cover and bagging of bunches of ‘Niagara Rosada’, in Almirante Tamandaré, PR, Brazil. Plastic cover used was of polyethylene with 250 µm of thickness and bagging of the bunches with white non-woven fabric bags. The treatments were: without plastic cover over the vineyard and without bagging of bunches (control); with plastic cover over the vineyard and without bagging of bunches; with plastic cover over the vineyard and with bagging of bunches; and without plastic cover over the vineyard and with bagging of bunches. To determine the quality of the grapes, we evaluated weight of the bunches and berry, width and length of the bunch, number of berries per bunch, total soluble solids (SS), titratable acidity (TA), pH, and SS/TA ratio. In both crop seasons, treatments with the protected plants or bunches were superior in all evaluated traits. The plastic cover and bagging of bunches delayed maturation and improved the physical and chemical characteristics of bunches and berries of ‘Niagara Rosada’.

Effect of Aqueous Neem Extract on Development of Pestalotia heterocornis Agent of Pestalotia Leaf Blight of Cashew in Far North Cameroon

Cashew (Anacardium occidentale L.) trees are threatened by my many fungal diseases, among which pestaliotiopsis occupies an important place in terms of damage created in Cameroon. The aim of the present study is to evaluate the effects of aqueous extract of neem seed (AENS) on the development of Pestalotia heterocornis, the causative agent of pestalotiopsis of cashew. Isolates of P. heterocornis were obtained from diseased cashew leaves collected in the orchads. The concentrations of AENS were C1 = 500 μg/ml, C2 = 50 μg/ml and C3 = 5 μg/ml. Mancozeb 80 WP (Mz) was used as positive control. Effect of Mancobeb 80WP on the growth and spore germination of isolates were performed. The effect of AENS on the plants was evaluated in vivo. Four (4) isolates of P. heterocornis were used. AENS C1 concentration reduced the growth of all isolates. The percentage of inhibition was ranged from 45 to 90 % with the other concentrations. AENS did not inhibited spore germination (0.0 %). But Mz totally inhibited conidia germination of all isolates. In vivo, AENS protected plants against P. heterocornis. AENS can be integrated in management of cashew plants against P. heterocornis.

Plant defense responses triggered by phytoseiid predatory mites (Mesostigmata: Phytoseiidae) are species-specific, depend on plant genotype and may not be related to direct plant feeding

Zoophytophagous arthropods can elicit plant defense responses affecting potential prey beyond predation. Phytophagy prevails as the main trigger for these responses, as in the case of Euseius stipulatus (Athias-Henriot) (Mesostigmata: Phytoseiidae), a predator occurring in citrus. Because other triggers cannot be excluded, our aim was to examine whether other phytoseiids co-occurring with E. stipulatus but not engaged in plant feeding [Neoseiulus californicus (McGregor) and Phytoseiulus persimilis Athias-Henriot] could induce similar responses (in terms of herbivore induced plant volatiles, HIPVs, and main defensive pathways), and how these affected the behavior of conspecifics and the shared prey, Tetranychus urticae Koch (Prostigmata: Tetranychidae). N. californicus triggered plant genotype-specific defense responses, including the production of different HIPVs compared to clean plants. However, we could not observe these effects for P. persimilis. T. urticae avoided better protected plants, because of stronger direct or indirect defense. As plants with weaker direct defense levels should offer higher prey densities, and those harboring conspecific predators represent higher risk of cannibalism, predators were expected to behave similarly. However, they did not. Our results demonstrate that plant defense triggered by phytoseiids is species-specific, depend on plant genotype and can be triggered by non-feeding activities. As N. californicus is a highly efficient predator used worldwide, further studies with this species are needed. Likewise, cineol, one of the volatiles identified in the blends triggered by this phytoseiid, could be used to manipulate the prey. These studies could pave the way for a more efficient use of phytoseiids in agroecosystems.