Biotic factors affect plant immune responses and plant resistance to pathogen infections. Despite the considerable progress made over the past two decades in manipulating genes, proteins and their levels from diverse sources, no complete genetic tolerance to environmental stresses has been developed so far in any crops. Plant defense response to pathogens, including Botrytis cinerea, is a complex biological process involving various changes at the biochemical, molecular (i.e. transcriptional) and physiological levels. Once a pathogen is detected, effective plant resistance activates signaling networks through the generation of small signaling molecules and the balance of hormonal signaling pathways to initiate defense mechanisms to the particular pathogen. Recently, studies using Arabidopsis thaliana and crop plants have shown that many genes are involved in plant responses to B. cinerea infection. In this article, we will review our current understanding of mechanisms regulating plant responses to B. cinerea with a particular interest on hormonal regulatory networks involving phytohormones salicylic acid (SA), jasmonic acid (JA), ethylene (ET) and abscisic acid (ABA). We will also highlight some potential gene targets that are promising for improving crop resistance to B. cinerea through genetic engineering and breeding programs. Finally, the role of biological control as a complementary and alternative disease management will be overviewed.

Plants have evolved with intricate mechanisms to cope with multiple environmental stresses. To adapt with biotic and abiotic stresses, plant responses involve changes at the cellular and molecular levels. The current study was designed to investigate the effects of combinations of different environmental stresses on the transcriptome level of Arabidopsis genome using public microarray databases. We investigated the role of cyclopentenones in mediating plant responses to environmental stress through TGA (TGACG motif-binding factor) transcription factor, independently from jasmonic acid. Candidate genes were identified by comparing plants inoculated with Botrytis cinerea or treated with heat, salt or osmotic stress with non-inoculated or non-treated tissues. About 2.5% heat-, 19% salinity- and 41% osmotic stress-induced genes were commonly upregulated by B. cinerea-treatment; and 7.6%, 19% and 48% of genes were commonly downregulated by B. cinerea-treatment, respectively. Our results indicate that plant responses to biotic and abiotic stresses are mediated by several common regulatory genes. Comparisons between transcriptome data from Arabidopsis stressed-plants support our hypothesis that some molecular and biological processes involved in biotic and abiotic stress response are conserved. Thirteen of the common regulated genes to abiotic and biotic stresses were studied in detail to determine their role in plant resistance to B. cinerea. Moreover, a T-DNA insertion mutant of the Responsive to Dehydration gene (rd20), encoding for a member of the caleosin (lipid surface protein) family, showed an enhanced sensitivity to B. cinerea infection and drought. Overall, the overlapping of plant responses to abiotic and biotic stresses, coupled with the sensitivity of the rd20 mutant, may provide new interesting programs for increased plant resistance to multiple environmental stresses, and ultimately increases its chances to survive. Future research directions towards a better dissection of the potential crosstalk between B. cinerea, abiotic stress, and oxylipin signaling are of our particular interest.

No abstract

No abstract

Plants have evolved with complex signaling circuits that operate under multiple conditions and govern numerous cellular functions. Stress signaling in plant cells is a sophisticated network composed of interacting proteins organized into tiered cascades where the function of a molecule is dependent on the interaction and the activation of another. In a linear scheme, the receptors of cell surface sense the stimuli and convey stress signals through specific pathways and downstream phosphorylation events controlled by mitogen-activated protein (MAP) kinases and second messengers, leading to appropriate adaptive responses. The specificity of the pathway is guided by scaffolding proteins and docking domains inside the interacting partners with distinctive structures and functions. The flexibility and the fine-tuned organization of the signaling molecules drive the activated MAP kinases into the appropriate location and connection to control and integrate the information flow. Here, we overview recent findings of the involvement of MAP kinases in major abiotic stresses (drought, cold and temperature fluctuations) and we shed light on the complexity and the specificity of MAP kinase signaling modules.

Botrytis cinerea is a dangerous plant pathogenic fungus with wide host ranges. This aggressive pathogen uses multiple weapons to invade and cause serious damages on its host plants. The continuing efforts of how to solve the “puzzle” of the multigenic nature of B. cinerea’s pathogenesis and plant defense mechanisms against the disease caused by this mold, the integration of omic approaches, including genomics, transcriptomics, proteomics and metabolomics, along with functional analysis could be a potential solution. Omic studies will provide a foundation for development of genetic manipulation and breeding programs that will eventually lead to crop improvement and protection. In this mini-review, we will highlight the current progresses in research in plant stress responses to B. cinerea using high-throughput omic technologies. We also discuss the opportunities that omic technologies can provide to research on B. cinerea-plant interactions as an example showing the impacts of omics on agricultural research.

Recombinant proteins expressed in plants have been emerged as a novel branch of the biopharmaceutical industry, offering practical and safety advantages over traditional approaches. Cultivable in various platforms (i.e. open field, greenhouses or bioreactors), plants hold great potential to produce different types of therapeutic proteins with reduced risks of contamination with human and animal pathogens. To maximize the yield and quality of plant-made pharmaceuticals, crucial factors should be taken into account, including host plants, expression cassettes, subcellular localization, post-translational modifications, and protein extraction and purification methods. DNA technology and genetic transformation methods have also contributed to great parts with substantial improvements. To play their proper function and stability, proteins require multiple post-translational modifications such as glycosylation. Intensive glycoengineering research has been performed to reduce the immunogenicity of recombinant proteins produced in plants. Important strategies have also been developed to minimize the proteolysis effects and enhance protein accumulation. With growing human population and new epidemic threats, the need for new medications will be paramount so that the traditional pharmaceutical industry will not be alone to answer medication demands for upcoming generations. Here, we review several aspects of plant molecular pharming and outline some important challenges that hamper these ambitious biotechnological developments.

Multiple inherent biases related to different citation practices (for e.g., self-citations, negative citations, wrong citations, multi-authorship-biased citations, honorary citations, circumstantial citations, discriminatory citations, selective and arbitrary citations, etc.) make citation-based bibliometrics strongly flawed and defective measures. A paper can be highly cited for a while (for e.g., under circumstantial or transitional knowledge), but years later it may appear that its findings, paradigms, or theories were untrue or invalid anymore. By contrast, a paper may remain shelved or overlooked for years or decades, but new studies or discoveries may actualize its subject at any moment. As citation-based metrics are transformed into "commercial activities," the "citation credit" should be considered on a commercial basis too, in the sense that "citation credit" should be shared out as a "citation dividend" by shareholders (coauthors) averagely or proportionally to their contributions but not fully appropriated by each of them. At equal numbers of citations, the greater number of authors, the lower "citation credit" should be and vice versa. Overlooking the presence of distorted and subjective citation practices makes many people and administrators "obsessed" with the number of citations to such an extent to run after "highly cited" authors and to create specialized citation databases for commercial purposes. Citation-based bibliometrics, however, are unreliable and unscientific measures; citation counts do not mean that a more cited work is of a higher quality or accuracy than a less cited work because citations do not measure the quality or accuracy. Citations do not mean that a highly cited author or journal is more commendable than a less cited author or journal. Citations are not more than countable numbers: no more, no less.