Editorial: Eliciting plant defense responses: From basic to applied science for sustainable agriculture

Plants constantly face a diversity of pathogens and insects that affect food production. Synthetic agrochemicals are often use to overcome these challenges. However, current demands for stringent worldwide regulatory policies led to the development of sustainable agriculture strategies, including naturally-derived molecules that elicit plant defense responses (Scariotto et al., 2021). The commercial use of these molecules is still limited, mostly due to poor knowledge on the molecular mechanisms producing their effects on plant metabolism. In recent decades, efforts have been directed toward understanding how individual molecules, such as immune receptors or microbial effectors, enable plants to perceive and respond to pathogens, insects, and other stresses. Furthermore, recent research on plant immunity has revealed high levels of complexity, including regulation mediated by micro-peptides and miRNA. Such knowledge opens the opportunity to link basic and applied science to facilitate using natural elicitors as a sustainable option for crop protection

Editorial: Insect physiological changes during insect-plant interaction

The interactions between phytophagous insects and their host plants result from a long and continuous evolutionary process (Beran and Petschenka, 2022). Such ecological relationships led to an extraordinary diversity of insects and shaped their complex physiological systems (Wheat et al., 2007). The impacts of host plants on the physiology of herbivorous insects have increasingly become a paramount focus that should not be ignored. Chemical compounds’ composition of plants have not only significant variations in the inter/intra species aspect but also show spatiotemporal variations in different developmental stages and tissue types, or under changeable environments in nature, which lead to the resource assimilation and fitness challenges of insects (Delucia et al., 2012; Brütting et al., 2017). These close interations with plants affect the ecological plasticity of the performance of insect herbivores (Barker et al., 2019). Currently, in-depth exploration of the host plants’ effect on insects has become a research hotspot of insect physiology, however to test the highly complex hypothesis can be difficult. The current Research Topic aimed to highlight the recent developments on 1) how physiological changes occurred in herbivores during their interaction with host plants, 2) how these physiological changes in insects could be affected by other biotic factors

Editorial: Molecular intricacies of Trichoderma-plant-pathogen interactions

Trichoderma spp. are widely used as plant disease biocontrol agents around the world (Guzmán-Guzmán, 2019). Initial research on Trichoderma focused on their biocontrol ability mediated by mycoparasitism and antibiosis. Trichoderma spp. are known for direct antagonistic action on plant pathogenic fungi, and more recently for indirect suppression via induced defense. Thus, with the discovery that Trichoderma spp. can internally colonize roots and invoke defense responses in plants, attention of the research community largely shifted toward understanding how the plants and Trichoderma communicate with each other leading to a symbiosis-like relationship (Harman et al., 2004; Hohmann, 2012). At the initial attachment stage, Trichoderma spp. are known to secrete hydrophobins that could aid in adhesion to the root surface (Viterbo and Chet, 2006). Following attachment, secretion of plant cell wall degrading enzymes like pectate lyase (Morán Diez et al., 2009) and swollenin (Brotman et al., 2008; Andberg et al., 2015; Cosgrove, 2017) could facilitate penetration. It is important to note that penetration into the root is limited, and indeed genes encoding plant cell wall degrading enyzymes are downregulated early in root colonization (Estrada-Rivera et al., 2020). This occurs along with high representation of glycosyl hydrolases in the secretome (Nogueira-Lopez et al., 2018). Soluble enzymes may still be present in the secretome after the corresponding transcripts decrease, highlighting the need for obtaining well-resolved time course experiments for both gene expression and protein abundance during early colonization events. Trichoderma fungi are known to secrete a large number of small secreted cysteine-rich proteins (SSCPs) that might be involved in modulation of plant defense, fine tuning of which may be responsible for the outcome of this association. Though not clearly established, it seems possible that Trichoderma SSCPs initially suppress plant defense, and once the colonization is complete, induces plant defense to enter into a symbiosis-like relationship. Unlike mycorrhiza, there seems to exist no specificity in Trichoderma-plant association, which appears to be quite universal. For example, AM mycorrhizal fungi cannot colonize cruciferous roots exhibiting a level of specificity, but Trichoderma can effectively colonize such roots, indicating a generalist type of lifestyle

Environmental growth conditions of Trichoderma spp. affects indole acetic acid derivatives, volatile organic compounds, and plant growth promotion

"Trichoderma species are soil-borne filamentous fungi widely utilized for their many plant health benefits, such as conferring improved growth, disease resistance and abiotic stress tolerance to their hosts. Many Trichoderma species are able to produce the auxin phytohormone indole-3-acetic acid (IAA), and its production has been suggested to promote root growth. Here we show that the production of IAA is strain dependent and diverse external stimuli are associated with its production. In in vitro assays, Arabidopsis primary root length was negatively affected by the interaction with some Trichoderma strains. In soil experiments, a continuum effect on plant growth was shown and this was also strain dependent. In plate assays, some strains of Trichoderma spp. inhibited the expression of the auxin reporter gene DR5 in Arabidopsis primary roots but not secondary roots. When Trichoderma spp. and A. thaliana were physically separated, enhancement of both shoot and root biomass, increased root production and chlorophyll content were observed, which strongly suggested that volatile production by the fungus influenced the parameters analyzed. Trichoderma strains T. virens Gv29.8, T. atroviride IMI206040, T. sp. "atroviride B" LU132, and T. asperellum LU1370 were demonstrated to promote plant growth through volatile production. However, contrasting differences were observed with LU1370 which had a negative effect on plant growth in soil but a positive effect in plate assays. Altogether our results suggest that the mechanisms and molecules involved in plant growth promotion by Trichoderma spp. are multivariable and are affected by the environmental conditions.

Trabajo remoto en la educación física inclusiva de pamplona alta, distrito de san juan de Miraflores – Lima, 2020

El propósito de la investigación fue determinar si el trabajo remoto incide en la educación física inclusiva en Pamplona alta, distrito de San Juan de Miraflores – Lima, 2020. Investigación de tipo básica, de enfoque cuantitativo, descriptivo, no experimental, correlacional causal y de diseño transversal, en una muestra de quince docentes de educación física de instituciones educativas públicas del sector de Pamplona Alta del distrito de San Juan de Miraflores, del departamento de Lima; usando la técnica de la encuesta y aplicando un cuestionario elaborado por los autores; contó con cuatro objetivos específicos y cuatro hipótesis específicas, que fueron demostradas a través de la prueba de hipótesis mediante el estadístico R de Pearson en el SPSS V.22; generando 12 tablas y 4 figuras que sustentan el desarrollo de la investigación. Los resultados obtenidos nos muestran que el trabajo remoto ha incido de manera positiva baja en la educación física inclusiva en Pamplona alta, distrito de San Juan de Miraflores – Lima, 2020; con un coeficiente de regresión r=0,327 por lo que se demuestra que existe una correlación positiva baja entre las variables trabajo remoto y educación física inclusiva; con un nivel significancia (sig.=0.003) que es menor a p-valor 0.05 (pvalor<0.05).Tesi

Histidine kinase two-component response regulators Ssk1, Skn7 and Rim15 differentially control growth, developmental and volatile organic compounds emissions as stress responses in Trichoderma atroviride

The Skn7, Ssk1 and Rim15 proteins are response regulators involved in osmotic, oxidative and nutritional stress in fungi. In order to verify the involvement of these genes in Trichoderma atroviride IMI206040’s growth, conidiation, direct antagonism against plant pathogens (Rhizoctonia solani and Sclerotinia sclerotiorum), production of volatile organic compounds (VOCs) with fungistatic effect, and interaction with plants (growth promotion), single mutants were generated, and the phenotypic patterns were analysed in comparison to the wild-type (wt) strain. The mutants were submitted to osmotic, oxidative, membrane and cell wall stress conditions in vitro. The Δskn7 and Δrim15 mutants did not show either significant differences at morphological level, or marked decreases in mycelial growth and conidiation in relation to wt, whereas Δssk1 had altered phenotypes in most conditions tested. The plant-growth promotion of Arabidopsis thaliana seedlings induced by VOCs was not quantitatively modified by any of the mutants in relation to the wt strain, although possible differences in secondary root hairs was noticed for Δrim15. The fungistatic activity was significantly altered for Δssk1 and Δrim15. Overall, the Δssk1 strain showed remarkable morphological differences, with decrease in mycelial growth and conidiation, being also affected in the antagonistic capacity against plant pathogens. The impacts demonstrated by the deletion of ssk1 suggest this gene has a relevant participation in the signalling response to different stresses in T. atroviride and in the interactive metabolism with phytopathogens and plants. On the other hand, unlike other fungal models, Skn7 did not appear to have a critical participation in the above-mentioned processes; Rim15 seemed to confirm its involvement in modulating cellular responses to nutritional status, although with a possible cross-talk with other cellular processes. Our results suggest that Ssk1 likely plays a key regulatory role, not only in basic metabolisms of T. atroviride, but also in biocontrol-related characteristics

Fungistatic activity mediated by volatile organic compounds is isolate-dependent in Trichoderma sp. “atroviride B”

Trichoderma spp. produce multiple bioactive volatile organic compounds (VOCs). While the bioactivity of VOCs from different Trichoderma species is well documented, information on intraspecific variation is limited. The fungistatic activity of VOCs emitted by 59 Trichoderma sp. “atroviride B” isolates against the pathogen Rhizoctonia solani was investigated. Eight isolates representing the two extremes of bioactivity against R. solani were also assessed against Alternaria radicina, Fusarium oxysporum f. sp. lycopersici and Sclerotinia sclerotiorum. VOCs profiles of these eight isolates were analyzed using gas chromatography–mass spectrometry (GC-MS) to identify a correlation between specific VOCs and bioactivity, and 11 VOCs were evaluated for bioactivity against the pathogens. Bioactivity against R. solani varied among the fifty-nine isolates, with five being strongly antagonistic. All eight selected isolates inhibited the growth of all four pathogens, with bioactivity being lowest against F. oxysporum f. sp. lycopersici. In total, 32 VOCs were detected, with individual isolates producing between 19 and 28 VOCs. There was a significant direct correlation between VOC number/quantity and bioactivity against R. solani. 6-pentyl-α-pyrone was the most abundant VOC produced, but 15 other VOCs were also correlated with bioactivity. All 11 VOCs tested inhibited R. solani growth, some by >50%. Some of the VOCs also inhibited the growth of the other pathogens by >50%. This study demonstrates significant intraspecific differences in VOC profiles and fungistatic activity supporting the existence of biological diversity within Trichoderma isolates from the same species, a factor in many cases ignored during the development of biological control agents

Effect of Sawdust Particle Size on Physical, Mechanical, and Energetic Properties of Pinus durangensis Briquettes

Particle size is a physical property that sometimes limits the quality of briquettes, so it is recommended to use different sizes in mixtures for their manufacture. The objective of this research was to evaluate the effect of different particle sizes of sawdust in mixtures on some physical, mechanical, and energetic properties of briquettes made from Pinus durangensis sawdust, as well as set the ranges within the appropriate values found to obtain desired values. Three particle sizes were established (large, medium, and small), and 10 mixtures were prepared using different percentages of each particle classification. The particle density, volumetric swelling, compressive strength, impact resistance index (IRI), and gross calorific value of the briquettes were evaluated. For the determination of optimal mixtures, the surface response methodology was used under a three-factor simplex-lattice model. The particle density values were in the range 0.92 to 1.02 g cm−3 and the volumetric swelling was 0.96 to 3.9%. The highest resistance to compression was 37.01 N mm−1, and the IRI was found in the range of 53 to 107%. The gross calorific values were from 19.35 to 21.63 MJ kg−1. The selection of different particle sizes for the mixtures increases the quality of the briquettes