scholarly journals Genome-Scale Genotype-Phenotype Matching of Two Lactococcus lactis Isolates from Plants Identifies Mechanisms of Adaptation to the Plant Niche

2007 ◽  
Vol 74 (2) ◽  
pp. 424-436 ◽  
Author(s):  
Roland J. Siezen ◽  
Marjo J. C. Starrenburg ◽  
Jos Boekhorst ◽  
Bernadet Renckens ◽  
Douwe Molenaar ◽  
...  
Keyword(s):  
Lactococcus Lactis ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Degradation Products ◽  
Phenotypic Diversity ◽  
Starter Cultures ◽  
Genome Sequences ◽  
Good Correspondence ◽  
Sequence Elements ◽  
Exopolysaccharide Biosynthesis

ABSTRACT Lactococcus lactis is a primary constituent of many starter cultures used for the manufacturing of fermented dairy products, but the species also occurs in various nondairy niches such as (fermented) plant material. Three genome sequences of L. lactis dairy strains (IL-1403, SK11, and MG1363) are publicly available. An extensive molecular and phenotypic diversity analysis was now performed on two L. lactis plant isolates. Diagnostic sequencing of their genomes resulted in over 2.5 Mb of sequence for each strain. A high synteny was found with the genome of L. lactis IL-1403, which was used as a template for contig mapping and locating deletions and insertions in the plant L. lactis genomes. Numerous genes were identified that do not have homologs in the published genome sequences of dairy L. lactis strains. Adaptation to growth on substrates derived from plant cell walls is evident from the presence of gene sets for the degradation of complex plant polymers such as xylan, arabinan, glucans, and fructans but also for the uptake and conversion of typical plant cell wall degradation products such as α-galactosides, β-glucosides, arabinose, xylose, galacturonate, glucuronate, and gluconate. Further niche-specific differences are found in genes for defense (nisin biosynthesis), stress response (nonribosomal peptide synthesis and various transporters), and exopolysaccharide biosynthesis, as well as the expected differences in various mobile elements such as prophages, plasmids, restriction-modification systems, and insertion sequence elements. Many of these genes were identified for the first time in Lactococcus lactis. In most cases good correspondence was found with the phenotypic characteristics of these two strains.

scholarly journals The Role of Arabinogalactan Type II Degradation in Plant-Microbe Interactions

2021 ◽  
Vol 12 ◽  
Author(s):  
Maria Guadalupe Villa-Rivera ◽  
Horacio Cano-Camacho ◽  
Everardo López-Romero ◽  
María Guadalupe Zavala-Páramo
Keyword(s):  
Cell Wall ◽  
Plant Defense ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Degradation Products ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Plant Interactions ◽  
Root Tips ◽  
Microbe Interactions

Arabinogalactans (AGs) are structural polysaccharides of the plant cell wall. A small proportion of the AGs are associated with hemicellulose and pectin. Furthermore, AGs are associated with proteins forming the so-called arabinogalactan proteins (AGPs), which can be found in the plant cell wall or attached through a glycosylphosphatidylinositol (GPI) anchor to the plasma membrane. AGPs are a family of highly glycosylated proteins grouped with cell wall proteins rich in hydroxyproline. These glycoproteins have important and diverse functions in plants, such as growth, cellular differentiation, signaling, and microbe-plant interactions, and several reports suggest that carbohydrate components are crucial for AGP functions. In beneficial plant-microbe interactions, AGPs attract symbiotic species of fungi or bacteria, promote the development of infectious structures and the colonization of root tips, and furthermore, these interactions can activate plant defense mechanisms. On the other hand, plants secrete and accumulate AGPs at infection sites, creating cross-links with pectin. As part of the plant cell wall degradation machinery, beneficial and pathogenic fungi and bacteria can produce the enzymes necessary for the complete depolymerization of AGs including endo-β-(1,3), β-(1,4) and β-(1,6)-galactanases, β-(1,3/1,6) galactanases, α-L-arabinofuranosidases, β-L-arabinopyranosidases, and β-D-glucuronidases. These hydrolytic enzymes are secreted during plant-pathogen interactions and could have implications for the function of AGPs. It has been proposed that AGPs could prevent infection by pathogenic microorganisms because their degradation products generated by hydrolytic enzymes of pathogens function as damage-associated molecular patterns (DAMPs) eliciting the plant defense response. In this review, we describe the structure and function of AGs and AGPs as components of the plant cell wall. Additionally, we describe the set of enzymes secreted by microorganisms to degrade AGs from AGPs and its possible implication for plant-microbe interactions.

Quantum Mechanical Calculations Suggest That Lignin Polymerization Is Kinetically Controlled

2019 ◽  
Author(s):  
Terry Gani ◽  
Michael Orella ◽  
Eric Anderson ◽  
Michael Stone ◽  
Fikile Brushett ◽  
...  
Keyword(s):  
Plant Cell ◽  
First Principles ◽  
Plant Cell Wall ◽  
Biological Processes ◽  
Plant Cell Walls ◽  
Biomass Valorization ◽  
Effective Strategies ◽  
Radical Coupling ◽  
Kinetically Controlled ◽  
Atomistic Models

Lignin is an abundant biopolymer important for plant function while holding promise as a renewable source of valuable chemicals. Although the lignification process in plant cell walls has been long-studied, a comprehensive, mechanistic understanding on the molecular scale remains elusive. A better understanding of lignification will lead to improved atomistic models of the plant cell wall that could, in turn, inform effective strategies for biomass valorization. Here, using first-principles quantum chemical calculations, we show that a simple model of kinetically-controlled radical coupling broadly rationalizes qualitative experimental observations of lignin structure across a wide variety of biomass types, thus paving the way for predictive, first-principles models of lignification while highlighting the ability of computational chemistry to help illuminate complex biological processes.

Ultrasound Assisted Solid-Liquid Extraction Devices - Harnessing Active Ingredients from Plant materials – Overview and Analysis

2020 ◽  
Vol 13 ◽  
Author(s):  
Venkatasubramanian Sivakumar
Keyword(s):  
Mass Transfer ◽  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Liquid Extraction ◽  
Active Ingredients ◽  
Plant Materials ◽  
Ultrasound Assisted ◽  
Solid Liquid Extraction ◽  
Solid Liquid

Background: In the growing environmental concern use of natural products, efficient processes and devices are necessary. Solid-Liquid extraction of active Ingredients from Plant materials is one of the important unit operations in Chemical Engineering and need to be enhanced. Objectives: Since, these active ingredients are firmly bound to the plant cell wall membrane, which pose mass-transfer resistance and need to get detached through the use of suitable process intensification tools such as ultrasound and suitable devices. Therefore, detailed analysis and review is essential on development made in this area through Publications and Patents. Hence, the present paper illustrates the development of ultrasound assisted device for solid-liquid extraction are presented in this paper. Methods: Advantages such as % Yield, Reduction in extraction time, use of ambient conditions, better process control, avoidance or minimizing multi stage extraction could be achieved due to the use of ultrasound in extraction as compared to conventional processes. Conclusions: Use of ultrasound to provide significant improvements in the extraction of Vegetable tannins, Natural dyes for application in Leather processing has been demonstrated and reported earlier. These enhancement could be possible through various effects of ultrasound such as better flow of solvents through micro-jet formation, mass transfer enhancement due to rupture of plant cell wall membranes through acoustic cavitation, better leaching due to micro-mixing and acoustic streaming effects. This approach would minimize material wastage; thereby, leading to eco-conservation of plant materials, which is very much essential for better environment. Hence, various methods and design for application of ultrasound assisted solid-liquid extractor device are necessary.

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