Decoding the photoprotection strategies and manipulating cyanobacterial photoprotective metabolites, mycosporine-like amino acids, for next-generation sunscreens.

The most recent evaluation of the impacts of UV-B radiation and depletion of stratospheric ozone points out the need for effective photoprotection strategies for both biological and nonbiological components. To mitigate the disruptive consequences of artificial sunscreens, photoprotective compounds synthesized from gram-negative, oxygenic, and photoautotrophic prokaryote, cyanobacteria have been studied. In a quest to counteract the harmful UV radiation, cyanobacterial species biosynthesize photoprotective metabolites named as mycosporine-like amino acids (MAAs). The investigation of MAAs as potential substitutes for commercial sunscreen compounds is motivated by their inherent characteristics, such as antioxidative properties, water solubility, low molecular weight, and high molar extinction coefficients. These attributes contribute to the stability of MAAs and make them promising candidates for natural alternatives in sunscreen formulations. They are effective at reducing direct damage caused by UV radiation and do not lead to the production of reactive oxygen radicals. In order to better understand the role, ecology, and its application at a commercial scale, tools like genome mining, heterologous expression, and synthetic biology have been explored in this review to develop next-generation sunscreens. Utilizing tactical concepts of bio-nanoconjugate formation for the development of an efficient MAA-nanoparticle conjugate structure would not only give the sunscreen complex stability but would also serve as a promising tool for the production of analogues. This review would provide insight on efforts to produce MAAs by diversifying the biosynthetic pathways, modulating the precursors and stress conditions, and comprehending the gene cluster arrangement for MAA biosynthesis and its application in developing effective sunscreen.

Xylopentose production from crop residue employing xylanase enzyme.

To produce xylo-oligosaccharides (XOS) from the agriculture waste, which included, green coconut and vegetable cocktail. The two pretreatment - hydrogen peroxide-acetic acid (HP-AC) and sodium hypochlorite-sodium hydroxide (SH-SH) - were used for this study. The optimal conditions for the pretreatment were 80 °C, 4.0 % NaClO, and 2 h, followed by 0.08 % NaOH, 55 °C, and 1 h. Further enzymatic hydrolysis of green coconut (GC) and vegetable cocktail (VC) were performed and found in case of GC, the best outcomes were observed. Different types of XOS were obtained from the treated biomass whereas a single type of XOS xylo-pentose was obtained in high quantity (96.44 % and 93.09 % from CG and VC respectively) with the production of other XOS < 2 %. This study presents a reasonably secure and economical method for turning secondary crop residue into XOS and fermentable sugars.

Cyanobacteria as a Promising Alternative for Sustainable Environment: Synthesis of Biofuel and Biodegradable Plastics.

With the aim to alleviate the increasing plastic burden and carbon footprint on Earth, the role of certain microbes that are capable of capturing and sequestering excess carbon dioxide (CO2) generated by various anthropogenic means was studied. Cyanobacteria, which are photosynthetic prokaryotes, are promising alternative for carbon sequestration as well as biofuel and bioplastic production because of their minimal growth requirements, higher efficiency of photosynthesis and growth rates, presence of considerable amounts of lipids in thylakoid membranes, and cosmopolitan nature. These microbes could prove beneficial to future generations in achieving sustainable environmental goals. Their role in the production of polyhydroxyalkanoates (PHAs) as a source of intracellular energy and carbon sink is being utilized for bioplastic production. PHAs have emerged as well-suited alternatives for conventional plastics and are a parallel competitor to petrochemical-based plastics. Although a lot of studies have been conducted where plants and crops are used as sources of energy and bioplastics, cyanobacteria have been reported to have a more efficient photosynthetic process strongly responsible for increased production with limited land input along with an acceptable cost. The biodiesel production from cyanobacteria is an unconventional choice for a sustainable future as it curtails toxic sulfur release and checks the addition of aromatic hydrocarbons having efficient oxygen content, with promising combustion potential, thus making them a better choice. Here, we aim at reporting the application of cyanobacteria for biofuel production and their competent biotechnological potential, along with achievements and constraints in its pathway toward commercial benefits. This review article also highlights the role of various cyanobacterial species that are a source of green and clean energy along with their high potential in the production of biodegradable plastics.

Transcriptome analysis of root-knot nematode (Meloidogyne incognita)-infected tomato (Solanum lycopersicum) roots reveals complex gene expression profiles and metabolic networks of both host and nematode during susceptible and resistance responses.

Root-knot nematodes (RKNs, Meloidogyne incognita) are economically important endoparasites with a wide host range. We used a comprehensive transcriptomic approach to investigate the expression of both tomato and RKN genes in tomato roots at five infection time intervals from susceptible plants and two infection time intervals from resistant plants, grown under soil conditions. Differentially expressed genes during susceptible (1827, tomato; 462, RKN) and resistance (25, tomato; 160, RKN) interactions were identified. In susceptible responses, tomato genes involved in cell wall structure, development, primary and secondary metabolite, and defence signalling pathways, together with RKN genes involved in host parasitism, development and defence, are discussed. In resistance responses, tomato genes involved in secondary metabolite and hormone-mediated defence responses, together with RKN genes involved in starvation stress-induced apoptosis, are discussed. In addition, 40 novel differentially expressed RKN genes encoding secretory proteins were identified. Our findings provide novel insights into the temporal regulation of genes involved in various biological processes from tomato and RKN simultaneously during susceptible and resistance responses, and reveal the involvement of a complex network of biosynthetic pathways during disease development.

Genome-wide identification and characterization of miRNAome from tomato (Solanum lycopersicum) roots and root-knot nematode (Meloidogyne incognita) during susceptible interaction.

Root-knot nematodes (RKNs, Meloidogyne spp.) are the most damaging plant parasites causing severe losses to crop production. The present study reports genome-wide identification and characterization of both tomato and RKN miRNAs simultaneously from RKN-infected susceptible tomato roots using high-throughput sequencing technique. RNAseq data from 11 small RNA libraries derived from 5 disease development stages identified 281 novel miRNAs of tomato in addition to 52 conserved and 4 variants of conserved miRNAs. Additionally, the same set of RNAseq data identified 38 conserved and 290 novel RKN miRNAs. Both tomato and RKN miRNAs showed differential expression at 5 stages of disease development based on digital expression profiles. In tomato, further validation through qRT-PCR confirmed that majority of miRNAs were significantly upregulated during susceptible response whereas downregulated during resistance response. The predicted targets of 8 conserved and 1 novel miRNAs were validated through 5'RLM-RACE. A negative correlation between expression profiles of a few conserved miRNAs (miR156, miR159, miR164 and miR396) and their targets (SBP, GAMYB-like, NAC and GRF1 transcription factor) was confirmed. A novel Sly_miRNA996 also showed a negative correlation with its target MYB-like transcription factor. These results indicate that the conserved and novel tomato miRNAs are involved in regulating developmental changes in host root during RKN infection. In RKN, the targets of conserved miRNAs were also predicted and a few of their predicted target genes are known to be involved in nematode parasitism. Further, the potential roles of both tomato and RKN miRNAs have been discussed.