Understanding CRISPR/Cas9: A Magnificent Tool for Plant Genome Editing

Nowadays, it is well known that archaea organisms as well as bacteria show an important range of defense mechanisms. Among others, a unique molecular system called CRISPR/Cas (clustered regularly interspaced short palindromic repeats) helps provide protection (adaptive guided immunity) athwart foreign nucleic acids, including plasmids and viral infections. As a typical immune response, CRISPR system is based on the acquisition of genetic records provided by infectious external agents, and in this sense, a high interference upon a new infection is unchained. In relation to plant research, less than 10 years ago, efforts to understand this peculiar mechanism and the possibility of being used in biotechnological processes have been focused on obtaining atavistic changes in different transformable vegetal specimens by inducing selective mutations into a reading frame that may be translated in a given moment (i.e., ORF; open reading frame). In light of the consideration that one common use of ORFs is to assist gene prediction processes, palindromic repeats are mostly based on the directed mutations via nonhomologous end joining. Although it is true that DNA-free editing techniques are now desirable for molecular crop breeding, CRISPR/Cas as a mutational regulatory system in plant biology may offer better complex genome rearrangements

The Extraordinary Nature of RNA Interference in Understanding Gene Downregulation Mechanism in Plants

Gene silencing (also known as ribonucleic acid [RNA] interference [RNAi] or interfering RNA) was first recognized in plants and is considered one of the most significant discoveries in molecular biology in the last several years. These short-chain ribonucleic acid molecules regulate eukaryotic gene expression. The phenomenon involves a process that promotes RNA transcripts degradation through complementarity between RNA molecules and RNAi transcripts, resulting in the reduction of their translation levels. There are two principal classes of regulatory RNA molecules: small interfering RNAs (siRNA) and microRNAs (miRNA). Both are generated from the cleavage of double-stranded self-complementary RNA hairpins by a DICER enzyme that belongs to the RNase III family. Small RNAs (of about 21–24 nucleotides in size) guide specific effector Argonaute protein to a target nucleotide sequence by complementary base pairing. Thereby, the effector protein complex downregulates the expression of RNA or DNA targets. In plants, cis-regulatory RNAi sequences are involved in defense mechanisms against antagonistic organisms and transposition events, while trans-regulatory sequences participate in growth-related gene expression. siRNA also performs neutral antiviral defense mechanisms and adaptive stress responses. This document is an attempt to scrutinize the RNAi nature in understanding gene downregulation mechanism in plants and some technical applications

ESTUDIO QUÍMICO DEL GUSANO BLANCO DEL MAGUEY Aegiale speriaris

Aegiale sperearís, mejor conocido como gusano blanco del maguey, es una larva de mariposa que habita en las pencas de los magueyes, considerada como un alimento típico mexicano, el cual forma parte de costumbres culturales ancestrales de este país; no obstante, poco se sabe de su composición química orgánica. Por tanto, el objetivo de este trabajo, fue realizar el estudio químico orgánico de Aegiale speñarís

ANTIBACTERIAL ACTIVITY AND VIRULENCE FACTORS INHIBITION BY Xylaria sp. (Xylariaceae, Ascomycota): A STUDY OF BIOACTIVE POTENTIAL

Background: The genus Xylaria comprises over 300 fungal species distributed worldwide that exhibit adaptability to various ecological roles. Consequently, their potential for the synthesis of bioactive molecules with antibacterial and antivirulence properties has been reported. Objective: To characterize the antibacterial and antivirulence properties of Xylaria sp. (OG-03) strain against phytopathogenic bacteria (Pseudomonas syringae, Pseudomonas syringae pv. tabaci, Pseudomonas putida, and Chryseobacterium sp.) and Chromobacterium violaceum 553, respectively. Methodology: A fungal strain was isolated and characterized morphologically and molecularly, and its evolutionary history was investigated through phylogenetic reconstruction. Mycelial growth was assessed in different culture media with natural substrates, and fungal extracts were obtained to evaluate minimal inhibitory (phytopathogenic bacteria) and antivirulence (biosensor strain) activities. Results: Morphological and molecular characterizations of the fungal strain suggested an indeterminate taxonomic classification at the species level within the genus Xylaria. The highest mycelial growth was observed in the REA culture medium, and the liquid rice extract promoted ectostomes proliferation. Fungal biomass extracts displayed antibacterial activity against P. syringae (MIC 7.81 µg/mL, 88% inhibition), Pseudomonas syringae pv. tabaci (MIC 1.95 µg/mL, 87% inhibition), Pseudomonas putida (MIC 1.95 µg/mL, 79.25% inhibition), and Chryseobacterium sp. (MIC 7.81 µg/mL, 85.03% inhibition), respectively. Antivirulence against C. violaceum reduced biofilm formation (125 µg/mL, 59% inhibition) and violacein production (62.5 µg/mL, 58% inhibition). Implications: Xylaria sp. exhibits antibacterial and antivirulence activity against phytopathogenic bacteria. Conclusions: The strain studied is suggested to be an undetermined taxon within the genus Xylaria. The results of biological assays indicated that the fungus possesses antibiotic properties against phytopathogenic bacteria and can inhibit virulence factors associated with quorum sensing