Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants

In changing environmental conditions, horticulture plants are affected by a vast range of abiotic and biotic stresses which directly and indirectly influence plant condition [...]

Transcriptomic and Metabolomic Analyses Provide Insights Into an Aberrant Tissue of Tea Plant (Camellia sinensis)

Tea plant (Camellia sinensis (L.) O. Kuntze) is one of the most important economic crops with multiple mutants. Recently, we found a special tea germplasm that has an aberrant tissue on its branches. To figure out whether this aberrant tissue is associated with floral bud (FB) or dormant bud (DB), we performed tissue section, transcriptome sequencing, and metabolomic analysis of these tissues. Longitudinal sections indicated the aberrant tissue internal structure was more like a special bud (SB), but was similar to that of DB. Transcriptome data analysis showed that the number of heterozygous and homozygous SNPs was significantly different in the aberrant tissue compared with FB and DB. Further, by aligning the unmapped sequences of the aberrant tissue to the Non-Redundant Protein Sequences (NR) database, we observed that 36.13% of unmapped sequences were insect sequences, which suggested that the aberrant tissue might be a variation of dormant bud tissue influenced by the interaction of tea plants and insects or pathogens. Metabolomic analysis showed that the differentially expressed metabolites (DEMs) between the aberrant tissue and DB were significantly enriched in the metabolic pathways of biosynthesis of plant hormones and biosynthesis of phenylpropanoids. Subsequently, we analyzed the differentially expressed genes (DEGs) in the above mentioned two tissues, and the results indicated that photosynthetic capacity in the aberrant tissue was reduced, whereas the ethylene, salicylic acid and jasmonic acid signaling pathways were activated. We speculated that exogenous infection induced programmed cell death (PCD) and increased the lignin content in dormant buds of tea plants, leading to the formation of this aberrant tissue. This study advanced our understanding of the interaction between plants and insects or pathogens, providing important clues about biotic stress factors and key genes that lead to mutations and formation of the aberrant tissue.

↵​Urdbean Leaf Crinkle Disease- Assessment of Seed Transmissibility and Its Effect on Yield and Seed Quality in Urdbean [Vigna mungo (L.) Hepper]

Background: Urdbean leaf crinkle disease (ULCD) is one of the most devastating biotic stress factors which is responsible for drastic yield loss in urdbean [Vigna mungo (L.) Hepper]. The etiology of ULCD is still unknown and there are conflicting reports on its transmission through seed, insect vectors, grafting and infected sap. Methods: Per cent seed transmission of ULCD had been studied during kharif, rabi and summer during the year 2019-2020 under natural and insect proof conditions. The effect on yield and seed quality parameters due to ULCD infection was studied. Urdbean cultivar VBN 8 was used in the present study. Result: The per cent seed transmission of ULCD was recorded ranging from 52.88 to 71.64% under natural conditions. In the insect proof glasshouse condition, the seed transmission was 83.62%. All the yield and seed quality parameters were adversely affected upon ULCD infection. The reduction in yield was recorded as 64.36% over the uninfected healthy plants. In ULCD infected seeds, the germination was reduced (84%) as compared to healthy seeds (92%).

N, P, K nutrition differentially affects the incidence and severity of the attack of pests and diseases in plants

Objective: To document and analyze relevant results reported on the relationships kept by the essential elements, nitrogen (N), phosphorus (P), and potassium (K) with biotic stress factors in higher plants. Design/methodology/approach: A bibliographic analysis was carried out using keywords related to the concepts of nutrient relationship with phytopathogens, plant fertilization and nutrition and biotic stress. Subsequently, the most relevant articles on N, P, and K and their relationship with pests and diseases were selected and analyzed. Results: The elements N, P, and K affect the development of pests on plants. Fertilization with N tend to increase the presence of pests, while fertilization with P and K decreases it. However, this cannot be generalized for all crops or pests. Limitations/implications of the study: Research on the effects of N, P, and K on the incidence of phytopathogens is limited and in most cases the mechanisms that determine such relashionship are not described. Findings/conclusions: Fertilization with N causes a higher incidence of pests and diseases in plants, while fertilization with P and K can contribute to reduce their incidence. However, due to the great diversity of responses, these statements are not applicable to all cases and depend on other factors such as the crop and the pest present in the agroecosystem. It is required to carry out studies that make it possible to clarify exactly how these essential elements influence the development of diseases in different crops, and thus be able to make nutrition recommendations in which limiting biotic factors are taken into account.

Root Endophytism by Pochonia chlamydosporia Affects Defense-Gene Expression in Leaves of Monocot and Dicot Hosts under Multiple Biotic Interactions

A study was carried out on the effect of the root endophytic fungus Pochonia chlamydosporia on plant systemic signal of defense related genes during fungal or nematode parasitism. Different biotic stress factors were examined, inoculating roots of dicot and monocot hosts with the endophyte, and measuring the expression of defense genes in leaves. A first greenhouse assay was carried out on expression of PAL, PIN II, PR1 and LOX D in leaves of tomato cv Tondino inoculated with Phytophthora infestans (CBS 120920), inoculating or not the roots of infected plants with P. chlamydosporia DSM 26985. In a second assay, plants of banana (Musa acuminata cv Grand Naine) were artificially infected with Fusarium oxysporum f. sp. cubense Tropical race 4 (TR4) and inoculated or not with DSM 26985. In a further experiment, banana plants were inoculated or not with P. chlamydosporia plus juveniles of the root knot nematode (RKN) Meloidogyne incognita. A similar assay was also carried out in vitro with adults and juveniles of the lesion nematode Pratylenchus goodeyi. Differential expression of the defense genes examined was observed for all plant-stress associations, indicative of early, upward systemic signals induced by the endophyte. Changes in expression profiles included a 5-fold down-regulation of PIN II at 2 dai in leaves of tomato plants treated with P. infestans and/or P. chlamydosporia, and the up-regulation of PAL by the endophyte alone, at 2 and 7 dai. In the TR4 assay, PR1 was significantly up-regulated at 7 dai in banana leaves, but only in the P. chlamydosporia treated plants. At 10 dai, PIN II expression was significantly higher in leaves of plants inoculated only with TR4. The banana-RKN assay showed a PR1 expression significantly higher than controls at 4 and 7 dai in plants inoculated with P. chlamydosporia alone, and a down-regulation at 4 dai in leaves of plants also inoculated with RKN, with a PR1 differential up-regulation at 10 dai. Pratylenchus goodeyi down-regulated PIN at 21 dai, with or without the endophyte, as well as PAL but only in presence of P. chlamydosporia. When inoculated alone, the endophyte up-regulated PR1 and LOX. The gene expression patterns observed in leaves suggest specific and time-dependent relationships linking host plants and P. chlamydosporia in presence of biotic stress factors, functional to a systemic, although complex, activation of defense genes.

A bibliometric analysis: How important is salicylic in response to the salinity from NaCl?

<p>Since plants are sessile due to their nature, they encounter- simultaneously or at different times numerous and various biotic and non-biotic stressors during their life span. Also, the severity and impacts of the stressors vary corresponding to the development stages and organs of the plant. Of the stress factors, salinity is considered as a major environmental constraint imposing limitations on growth, development, crop productivity, and quality of the plants in many regions of the world. Therefore, the studies concerned with salinity and its effects on plants are of the fundamental interests for agricultural issues. In order to alleviate the possible damages of salinity, exogenous applications of salicylic acid are of the common techniques used.  Herewith the study, the profiles of original and review articles under the topic of salicylic acid and salinity were examined by bibliometric analysis using VOSviewer tool. Along with the present study, it was aimed to answer the following research questions (RQ) associated to the researches regarding salt stress and salicylic acid interaction.</p><p>RQ1: Which plant species have been more focused for the studies?</p><p>RQ2: What kind of biochemical, physiological and molecular parameters have been used for analysis?</p><p>RQ3: How important the concentration of salicylic acid is? How important the mode of application of salicylic acid is?</p><p>RQ4: What are the research trends regarding salinity stress and salicylic acid considering the number and year of the publications, number of authors, main theme of the studies, country of the publications, core journals, the most cited documents etc.?</p><p>RQ5:  What is the spatial distribution of the researches? Do salinity stress faced countries mostly carry out the studies or not, considering the attributes influential on the performing the studies?</p><p>SCOPUS database was used for retrieving the related documents. For extracting documents, the following selection or limitation criteria were applied to profile the study concerned with salicylic acid and salinity interaction; (TITLE-ABS-KEY (salicylic AND acid)) AND (salt AND stress OR NaCl OR saline AND conditions OR salinity) AND (LIMIT-TO (SUBJAREA, "AGRI") OR LIMIT-TO (SUBJAREA, “BIOC")). Accordingly, 2,067 document results were retrieved. Then all documents were selected and exported to the CSV Excel. The documents were analyzed and visualized using VOSviewer tool. </p><p>Accordingly, two main salicylic acid research clusters according to the most relevant terms were identified. First cluster was composed of abiotic stress terms and related antioxidant activity and enzymes. The first cluster can be considered as biochemistry and abiotic stress. The second cluster was related to the biotic stress factors and molecular biology approaches. For the keyword analysis, various clusters regarding hormonal cross-talks, antioxidant enzymes with oxidative stress, biotic stress factors, and osmoprotectants were composed. According to the country analysis, China, United States, Pakistan, South Korea, and Oman were grouped together in same cluster. India, Iran, Saudi Arabia, and Malaysia were in the same cluster. The results were discussed in comparison.</p><p><strong>Keywords: </strong>Salicylic acid, salinity, bibliometric analysis, abiotic and biotic stress</p>

Assessment of bread wheat (Triticum aestivum L.) genotypes based on their agronomic characters and tolerance to biotic stress

The aim of the study was to investigate the occurrence and severity of biotic stress factors, quality and agronomic parameters and its effect on yield and quality character of wheat genotypes. The experiment was conducted at Trakia Agricultural Research Institute, Edirne experimental area, during 2013-2015 cropping years. Grain yield, days of heading, plant height, 1000-kernel weight, test weight, protein ratio, leaf rust, stripe rust, Septoria leaf spot and relationship among these parameters were investigated. Based on a two years data, apart from protein content, other parameters showed significant difference (p<0.05). When compared to the mean yields in both cropping years, the genotypes Gelibolu and BBVD-3, BBVD-4, BBVD-9 genotypes were determined the better-adapted genotypes under target environment. Cultivar Aldane and TCI011322-8 line was detected as very tolerant to leaf rust and stripe rust in both years under the infection of field condition. Aldane had higher protein ratio, 1000-kernel weight and test weight. Grain yield was positively correlated with test weight and negatively correlated with foliar diseases. A highly significant negative correlation was determined between grain yield and plant height in both growing years. Leaf rust and Septoria tritici leaf disease had negative effect on protein ratio in both years. There was a significant positive relation between 1000-kernel weight and test weight. Results of the study indicated that based on biotic stress factors BBVD-6, BBVD-7 and TCI011322-8 are promising lines that need to be improved a bit further.

Distribution range of parasitic plants from Cuscuta L. and Orobanche L. genera in Ukraine

Aim. The current paper addresses the distribution of parasitic plants from Cuscuta L. (Convolvulacae) and Orobanche L. (Orobanchaceae) genera in Ukraine based on the analysis of the herbarium specimens from the National Herbarium of M.G. Kholodny Institute of Botany, NAS of Ukraine (KW) and literature. Methods. In order to study the places of growth of the dodder and broomrape the traditional method based on the development of literary sources and herbarium funds. Results. About 1600 samples from KW were analyzed and data is summarized in tables. Conclusions. It was found that the distribution range of these parasitic plants is attributed mostly to the Steppe natural zone of Ukraine including the Crimean Peninsula. The results will be used in further research to develop an efficient strategy of parasitic phytoquarantine species control.Keywords: biotic stress factors, parasitic plants, dodder, broomrape.