Phenology is an important ecological feature that can be influenced by many abiotic aspects. For example, the decrease in temperature along an altitudinal gradient display a fundamental role in the phenophases it affects the life cycle and activity of insects and herbivores, therefore, mountainous regions are great sites to perform studies to help the understanding of the reproductive cycle of plants. In this work, the phenological cycle and leaf damage rate caused by herbivores in Trifolium repens L. were observed, among three different altitudes (1.700, 2.000 and 2.400 m) in the Itatiaia National Park, from June to August of 2021 and statistical analysis were performed using linear mixed effects models. Preliminary results show that altitude affected vegetative phenophases (number of open leaves, shoots and abscissions) and herbivory (P < 0.01). The highest altitude sampled stands out for having a less open and damaged leaves, and for being the only altitude without any flowering events. However, due to low intensity of this phenophase at other altitudes, it wasn’t possible to determine if altitude is in fact affecting flowering. Nevertheless, the influence of growing season climate on phenology is often observed in transplanting experiments, in which at lower altitudes plants typically develop earlier than those in their high altitude native sites. As for the damage caused by herbivores, it was expected that the highest altitude would present a lower damage rate than the others sites, since it is known that environmental conditions of higher altitudes (such as decreased temperature) can reduce the aptitude of various insects.

Plant health is a major target in breading programs because crops are under constant biotic stress, and climate change is exacerbating pests and disease negative impacts in agriculture. Obtaining crop varieties armed with better defences is a potential strategy to reduce losses from biotic attacks. Plant cell walls perform crucial roles on many physiological processes, and under biotic stress, play crucial defensive roles as protecting barrier, as well as a source of integrity signalling molecules. Plant immunity has evolved a complex multi-layered system which first line of defence is initiated by conserved molecular patterns coming from pathogens, named pathogen-associated molecular patterns or PAMPs, or from their own corrupted cell walls due to pathogen invasion, named damaged-associated molecular patterns or DAMPs. Accumulating evidence from cell wall mutants has unveiled several components and mechanisms of plant innate immunity under biotic stresses, mostly in Arabidopsis, but still little is known from species with agronomic interest as strawberry. Our group has an established strawberry transgenic collection of cell wall mutants. Among them, RNAseq expression profiles of FaPG1 mutants has shown downregulation of other cell wall related genes than FaPG1 [1], but the mechanisms underneath required further investigation. FaPG genes code for enzymes with endo-PG activity related to oligogalacturonic acid (OGA) release, which would be associated to the changes in gene expression of other cell wall genes than FaPG. In this work, postharvest assays of FaPG1 fruits showed not only the increased fruit firmness typical of this mutant, but a better resistance to fungal infections by Botrytis cinerea, enhancing fruit shelf life in comparison with control fruits. OGAs are well known molecules with DAMP activity, and the alteration of quantity and/or structure of OGAs in this FaPG1 lines could be related to the increased resistance to B. cinerea. Then, next steps will be to determine whether the differential biotic resistance of this transgenic strawberry line is due to modified DAMPs and assess its potential use as strategic tools to enhance plant resistance in strawberry crops.

References

1. Paniagua et al (2020). Elucidating the role of polygalacturonase genes in strawberry fruit softening. Journal of Experimental Botany, 71(22), 7103-7117.

Acknowledgments

This study was supported by the project PID2020-118468RB-C21, Ministerio de Ciencia e Innovación of Spain and B1-2020_09 funds from the Universidad de Málaga. I would like to thank David Vela for kindly provide the Botrytis cinerea strain B05.10.

Metal(loid)s are toxic to animal life, human health, and plants, therefore, their removal from polluted areas is imperative in order to minimize their impact on the ecosystems. The use of plant-amendment-microorganism synergy is a promising option, but not yet fully explored, to manage lands contaminated with metal(loid)s. However, molecular factors and mechanisms underlying this interaction are also almost unknown. The aim of the present study was to characterize Arabidopsis thaliana growth and response on arsenic and lead polluted soil. To accomplish this aim, a pot experiment was performed testing the effect of biochar and/or autochthonous metal(loid) resistant Bacillus isolate on physico-chemical soil properties and on plant growth and metal(loid) uptake/intake. Furthermore, bioinformatics-assisted proteomics approach was used to understand common and specific mechanisms regulating plant growth and metal(loid) tolerance in tested conditions. Results showed that biochar and/or Bacillus induced significant and positive effects on soil properties, increasing pH, C_tot, N_tot and P_tot concentrations and decreasing nutrients (N_av and P_av), As and Pb availability. Plant growth was also enhanced by addition of biochar and/or inoculum, reaching the maximum when biochar and bacteria were combined. The deciphering of molecular mechanisms revealed that combination of biochar and bacterial inoculation mitigate Arabidopsis growth and defense tradeoff and underline the great potential of plant-biochar-inoculum synergic application in more effective and large scale-up phytostabilizing systems.

Tamarillo (Solanum betaceum Cav.) is a Solanaceae tree cultivated for its edible fruits. Under specific stimuli, indirect somatic embryogenesis (SE) originates distinct calli: embryogenic (EC) and non-embryogenic (NEC). Both types proliferate, but only EC originates somatic embryos. The presence of secondary metabolites is known to influence induction and embryogenic competence. The objective of this work is to study some of these compounds on SE.

Leaf segments from in vitro established clones were cultivated on solid Murashige and Skoog medium supplemented with sucrose (26 mM) and picloram (20 µM). Phenolic acid influence was tested using caffeic acid (896 and 448 µM), flavonoid were assayed with rutin (197.5 and 98.75µM). Anthranilic acid, an amidobenzoic acid, was also tested (1164.8 and 582.4 µM). Additionally, previously induced EC and NEC lines were grown in liquid medium with the highest concentrations of each compound.

Results showed highest dedifferentiation rates (>90%) in the control and when rutin and caffeic acid were tested, whereas lower concentrations inhibit dedifferentiation. In contrast, the compounds seem to inhibit growth of established calli without affecting protein, phenolic acids and flavonoid levels, measured by spectrophotometric methods. Anthranilic acid completely inhibited both induction and calli growth.

The results seem to present a correlation of some secondary metabolites with dedifferentiation rates during induction and a tendency to inhibit growth of established calli, probably related to metabolic effects. Further studies are underway to further characterize the dose-response relation of these compounds and molecular mechanism underlying this phenotypic effect.

Prevalence of iron deficiency (ID) in upland rice under alkalinity stress is capable of constraining its production. This investigation aimed to explicate the physiological basis of ID tolerance in some upland rice genotypes. Eighty upland rice genotypes were characterised for ID tolerance at seedling growth stage in a sand-culture hydroponics with varying NaHCO₃ concentrations (0, 15 and 25 mM). The treatments were arranged in completely randomised design with three replicates. Significant (P < 0.05) decrease was observed on leaf iron concentration, SPAD meter readings, leaf photosynthetic efficiency, quantum yield and growth variables with increasing concentration of NaHCO₃. Iron tolerance index was further estimated based on these parameters and used for ranking the genotypes. Significant (P < 0.05) decrease was observed on all physiological and growth variables measured with increasing concentration of NaHCO₃. Based on iron tolerance index, Caipo and NERICA 7 were identified as the most and least tolerant to iron deficiency respectively. The basis of iron deficiency tolerance is discussed in relation to the stability of photosynthetic apparatus and plant growth under alkalinity stress.

In agriculture, microbial tools including biological fertilizers and biological control agents (i.e., biocontrol agents), have been used by mankind for several hundreds of years, and provide beneficial results for plant growth and health, respectively. In the broadest sense, the biological control can be defined as the use of microbial inoculants potentially replacing harmful pesticides, to control pests, plant pathogens and weeds. In this regard, both human activities and the use of resistant plants may be included.

The formulation of biocontrol agents from living organisms has been reported using several experimental conditions in laboratory scale. However, a large number of studies have shown that the biocontrol capacity can result from production of antibiotic compounds, or enzymes capable of fungal cell wall lysis and preventing pathogens from infecting the plant.

As a source of production of antibiotics and antifungal enzymes (e.g., chitinases, cellulases β-glucanases, proteases, lipases, etc.), biocontrol strains-based research is developing rapidly through the innovation and improvement of raw materials, formulations, preparation process, method for extracting, and production technology, as well as applications. This is evident also from the elevation in the number of patent applications filed each year worldwide in this area of biocontrol agents research and development.

This work, in the form of a patent analysis, which is a family of techniques for studying the information present within and attached to patents, describes the state of the art by introducing what has been patented in relation to biocontrol agents regarding to preparation methods/process, formulations and applications. Furthermore, this work gives a competitive analysis of the past, present and future trends in the biological control and leads to various recommendations that could help one to plan and innovate research strategy.

Numerous changes in environmental conditions are becoming the main cause of plant stress in the current scenario. Abiotic stress is the most concerning among those as it may affect the efficiency of crops, decrease the plant yield, deteriorate the quality of the crop, its vigour and might affect plant germination too. The regulation of these effects comprises transcriptional factors, that control expression of a gene by requisite to an explicit supporter of DNA sequences. The responses due to stress-induced by salt involves transcription factors viz. AP2/EREBP, bZIP/HDZIPs, myb proteins, putative zinc finger proteins, leucine zipper DNA binding proteins and DRE-associated binding aspects. Principally, AP2/ERF domain proteins consist of DREB or CBF proteins binding to C-repeats or dehydration response elements (DRE). These transcription factors are prevailing to aim for the genetic resistance towards abiotic stress in crops.

Apart from many crucial roles in cellular processes and signaling pathways, myo-inositol is also considered as an important osmoprotectant, which is directly involved in abiotic stress management in plants. Myo-inositol monophosphatase (IMP) catalyses the conversion of inositol 1-phosphate to myo-inositol, the second step in inositol biosynthesis. We have isolated IMP (CaIMP) from drought tolerant legume Chickpea (Cicer arietinum). The stress-induced increased accumulation of inositol has been reported in chickpea; however, the role and regulation of IMP is not well defined in response to stress.

We have demonstrated the significance of IMP in abiotic stress tolerance and thus explained its role in improving seed germination and plant growth under variety of stresses including drought and salt stress. Biochemical study revealed that CaIMP encodes a lithium-sensitive phosphatase enzyme with broad substrate specificity, it has been found to be implicated in both inositol and ascorbate biosynthesis. Apart from its main substrate Inositol 1-P and Galactose 1-P, CaIMP was also able to hydrolyze other substrates like Phytate, Fructose 1,6 bis-P. Our results indicate that, CaIMP possibly link various metabolic pathways. The transcript level of IMP has also been studied and found to be increased in different abiotic stresses.

We have also identified two IMP like proteins from chickpea; CaIMPL1 and CaIMPL2. Not much is known about the functions of IMPL. We have checked transcript level of both CaIMPL1 and CaIMPL2 under different abiotic stresses and hormone treatments in chickpea. Interestingly, differential expression of CaIMPL1 and CaIMPL2 were observed under different abiotic stresses. Similar to CaIMP, it also showed induction by ABA treatment. Our work also signifies the role of CaIMPL2 in Histidine pathway as it was able to catalyze the dephosphorylation of Histidinol 1-P, however IMPL1 was mostly involved in the hydrolysis of D-Ins 3-P and D Gal 1-P. Given the relation between IMP, IMPL1 and IMPL2, the difference in substrate specificity among these highly homologous enzymes suggests that the genes encoding these enzymes have diverged evolutionarily. Also, we have shown that broad substrate specificity of CaIMP enzyme is because of presence of very peculiar flexible loop structure and dynamic nature of active site.

Although climate scenarios have predicted an increase in CO₂ concentration that may favor C assimilation, previous studies show that, processes involved in biochemical and/or stomatic processes might reduce photosynthetic efficiency under elevated [CO₂]. Among others, [CO₂] impact on crop phenology, together with nutrient assimilation and translocation factors have been identified as relevant ones conditioning photosynthetic performance. In this study, the effect of elevated [CO₂] (400 versus 700 ppm) on photosynthetic apparatus was characterized through the corresponding gas exchange, chlorophyll fluorescence analyses combined with the determination of genes involved in light reactions (ferredoxin-NADP(H) oxidoreductase and ferredoxin), CO₂ diffusion (CA1, CA2, CA3) and N transport (AMT1.2, NRT1.1 and NRT2.1) as well as primary metabolites like carbohydrates and secondary metabolites like cytokinins contents were studied in durum wheat (Triticum durum, var. Amilcar) plants. Our results show that photosynthetic machinery was affected differently in plants at the end of elongation stage (Z39) and at the beginning of ear emergence (Z51). Sucrose was accumulated under elevated CO₂ conditions in leaves of wheat at Z39, whereas starch was the carbohydrate accumulated at Z51. Both sucrose and starch accumulation in leaves were significantly correlated with the decrease of Vc_max in these plants. Wheat plants exposed to elevated CO₂ presented high contents of zeatin and isopentenyl adenine in leaves that may promote N reallocation, delay senescence and prolong C assimilation in these plants. The current study highlights the importance of a deeper characterization target C and N metabolic pathways in crops during the different phonologic periods. Furthermore, the relevance of apical leaves as sources for developing organs is described in this study.

Developing a method to store valuable genotypes is very important for Salvia officinalis, which is an insect-pollinated plant and flowers in the second year of cultivation from seed. Moreover, somatic seeds can ensure the storage of plant line with a guarantee of genetic homogeneity and propagation of variable genotypes such as transgenic plants. In this context, research into the improvement of biotechnological methods for the production of high-quality somatic seeds is highly important. Current research has attempted to produce and convert somatic seeds that would enable the long- or medium-term preservation of valuable sage genotypes. The creation of artificial seeds consisted in placing explants capable to regenerating into plants in a protective casing. The apical and axillary buds were collected from the multi-shoot cultures, encapsulated with 1.2% sodium alginate solution, and then dripped into the 200 mM CaCl₂ solution. The occurring reaction of exchanging calcium ions with sodium ions leads to the formation of a beads with a hard polymer coat. After production, somatic seeds were placed on MS medium containing 0.3 mg L^-1 of BAP to convert them. The method of obtaining somatic seeds used in this study allowed to obtain a high level of conversion of seeds into plants using apical buds (85%), and slightly lower in the case of axillary buds (62.5%). However, the difference in seed viability in the ANOVA analysis of variance was at the level of p <0.01. Therefore, it can be assumed that the usefulness of the developed method applies to both initial explants. The obtained results concerning the formation and conversion of somatic seeds allowed to obtain a high level of plant viability, which may prove the usefulness of the method of storing valuable Salvia officinalis genotypes.