Insights into pectin O-acetylation in the plant cell wall: structure, synthesis, and modification.

O-Acetyl esterification is an important structural and functional feature of pectins present in the cell walls of all land plants. The amount and positions of pectin acetyl substituents varies across plant tissues and stages of development. Plant growth and response to biotic and abiotic stress are known to be significantly influenced by pectin O-acetylation. Gel formation is a key characteristic of pectins, and many studies have shown that gel formation is dependent upon the degree of acetylation. Previous studies have indicated that members of the TRICHOME BIREFRINGENCE-LIKE (TBL) family may play a role in the O-acetylation of pectin, however, biochemical evidence for acceptor specific pectin acetyltransferase activity remains to be confirmed and the exact mechanism(s) for catalysis must be determined. Pectin acetylesterases (PAEs) affect pectin acetylation as they hydrolyze acetylester bonds and have a role in the amount and distribution of O-acetylation. Several mutant studies suggest the critical role of pectin O-acetylation; however, additional research is required to fully understand this. This review aims to discuss the importance, role, and putative mechanism of pectin O-acetylation.

Optimization of Micropropagation and Genetic Transformation Protocols for Paulownia elongata : A Short Rotation Fast Growing Bioenergy Tree.

Various steps of micropropagation include selection of suitable explant, establishment of adventitious shoot induction cultures, proliferation, rooting, and acclimatization of the resulting plantlets. A systematic protocol is provided for the micropropagation and Agrobacterium tumefaciens-mediated genetic transformation of a fast growing, multipurpose tree, Paulownia elongata. Our studies show that optimum shoot induction is on half leaf with petiole explant on MS medium supplemented with 25 µM thidiazuron and 10 µM indole-3 acetic acid. Micropropagation protocols provided here are applicable to explants collected from the primed in vitro raised seedlings on MS medium containing 2.5 µM 6-benzylaminopurine (BAP) or actively growing shoots collected from greenhouse or field growing plants. We also discuss a possible role of "Python" script guided protocol optimization for higher and consistent multiplication of shoots that can be very helpful for scaled up production in commercial settings. To facilitate future plant improvement and gene editing possibilities, an A. tumefaciens based genetic transformation protocol and molecular identification of transgenic plants using Polymerase Chain Reaction (PCR) and Reverse Transcriptase-PCR (RT-PCR) techniques have also been optimized.

Long-Term Maintainable Somatic Embryogenesis System in Alfalfa (Medicago sativa) Using Leaf Explants: Embryogenic Sustainability Approach.

Alfalfa (Medicago sativa) is one of the most important forage legume crops because of its mass production and high feeding value. It originated in Asia and is one of the most ancient plants cultivated throughout the world as a fodder. Despite the well-studied somatic embryogenesis of alfalfa, there is a lack of a long-term maintainable somatic embryogenic system. Every time an embryogenic callus culture must be started from new explants, which is laborious, costly and time consuming. In addition to this, endogenous microorganisms present in ex vitro explants of alfalfa can often cause contamination, reducing the efficiency of callus culture. An attempt was made to establish long-term continuous somatic embryogenesis system in alfalfa using cultivar Regen-SY. Nine somatic embryogenesis pathways were studied and evaluated for embryo yield, plant conversion rate and embryogenic sustainability. Somatic embryos passed through the same stages (globular, heart-shaped, torpedo and cotyledonary) as characteristic of the zygotic embryo and secondary somatic embryogenesis was also observed. B5H-B5 system showed the highest embryo yield and plant conversion rate whereas SH4K-BOi2Y system demonstrated the highest embryogenic sustainability and maintained the embryogenic potential even after six subculture cycles. Scanning electron microscopy was applied to study the morphology of the somatic embryos and secondary somatic embryogenesis. Therefore, long-term maintainable somatic embryogenesis system protocol was developed through this study, which will help to enhance and accelerate the alfalfa biotechnology research.