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Gene-for-gene Relationship
The gene-for-gene relationship is a concept in plant pathology that plants and their diseases each have single genes that interact with each other during an infection. It was proposed by Harold Henry Flor who was working with rust (''Melampsora lini'') of flax ('' Linum usitatissimum''). Flor showed that the inheritance of both resistance in the host and parasite ability to cause disease is controlled by pairs of matching genes. One is a plant gene called the resistance (''R'') gene. The other is a parasite gene called the avirulence (''Avr'') gene. Plants producing a specific R gene product are resistant towards a pathogen that produces the corresponding ''Avr'' gene product. Gene-for-gene relationships are a widespread and very important aspect of plant disease resistance. Another example can be seen with '' Lactuca serriola'' versus '' Bremia lactucae''. Clayton Oscar Person was the first scientist to study plant pathosystem ratios rather than genetics ratios in host-paras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Pathology
Plant pathology or phytopathology is the scientific study of plant diseases caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Plant pathology involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases. Plant pathogenicity Plant pathogens, organisms that cause infectious plant diseases, include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. In most plant pathosystems, virulence depends on hydrolases and enzymes that degrade the cell wall. The vast majority of these act on pectins (for example, pectinesterase, pectate lyase, and pectinases). For microbes, the cell wall polysaccharides are both a food source and a barrier to be overcome. Many path ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucine Zipper
A leucine zipper (or leucine scissors) is a common three-dimensional structural motif in proteins. They were first described by Landschulz and collaborators in 1988 when they found that an enhancer binding protein had a very characteristic 30-amino acid segment and the display of these amino acid sequences on an idealized alpha helix revealed a periodic repetition of leucine residues at every seventh position over a distance covering eight helical turns. The polypeptide segments containing these periodic arrays of leucine residues were proposed to exist in an alpha-helical conformation and the leucine side chains from one alpha helix interdigitate with those from the alpha helix of a second polypeptide, facilitating dimerization. Leucine zippers are a dimerization motif of the BZIP domain, bZIP (Basic-region leucine zipper) class of eukaryotic transcription factors. The bZIP domain is 60 to 80 amino acids in length with a highly conserved DNA binding basic region and a more divers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arginine
Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidinium, guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the amino and guanidino groups are protonated, resulting in a cation. Only the -arginine (symbol Arg or R) enantiomer is found naturally. Arg residues are common components of proteins. It is Genetic code, encoded by the DNA codon table, codons CGU, CGC, CGA, CGG, AGA, and AGG. The guanidine group in arginine is the Precursor (chemistry), precursor for the biosynthesis of nitric oxide. Like all amino acids, it is a white, water-soluble solid. The one-letter symbol R was assigned to arginine for its phonetic similarity. History Arginine was first isolated in 1886 from Lupinus luteus, yellow lupin seedlings by the German chemist Ernst Schulze (chemist), Ernst Schulze and his assistant Ernst Steiger. He named it from the Greek ''árg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proline
Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group but is rather a secondary amine. The secondary amine nitrogen is in the protonated form (NH2+) under biological conditions, while the carboxyl group is in the deprotonated −COO− form. The "side chain" from the α carbon connects to the nitrogen forming a pyrrolidine loop, classifying it as a aliphatic amino acid. It is non-essential in humans, meaning the body can synthesize it from the non-essential amino acid L-glutamate. It is encoded by all the codons starting with CC (CCU, CCC, CCA, and CCG). Proline is the only proteinogenic amino acid which is a secondary amine, as the nitrogen atom is attached both to the α-carbon and to a chain of three carbons that together form a five-membered ring. History and etymology Proline was first isolated in 1900 by Richard Willstätter who obtained the amino a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophobic
In chemistry, hydrophobicity is the chemical property of a molecule (called a hydrophobe) that is seemingly repelled from a mass of water. In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thus, prefer other neutral molecules and nonpolar solvents. Because water molecules are polar, hydrophobes do not dissolve well among them. Hydrophobic molecules in water often cluster together, forming micelles. Water on hydrophobic surfaces will exhibit a high contact angle. Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general. Hydrophobic materials are used for oil removal from water, the management of oil spills, and chemical separation processes to remove non-polar substances from polar compounds. The term ''hydrophobic''—which comes from the Ancient Greek (), "having a fear of water", constructed Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 appear in the genetic code of life. Amino acids can be classified according to the locations of the core structural functional groups ( alpha- , beta- , gamma- amino acids, etc.); other categories relate to polarity, ionization, and side-chain group type ( aliphatic, acyclic, aromatic, polar, etc.). In the form of proteins, amino-acid '' residues'' form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life on Earth and its emergence. Amino acids are formally named by the IUPAC- IUBMB Joint Commi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucine
Leucine (symbol Leu or L) is an essential amino acid that is used in the biosynthesis of proteins. Leucine is an α-amino acid, meaning it contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α-Carboxylic acid, carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain Isobutyl, isobutyl group, making it a Chemical polarity, non-polar Aliphatic compound, aliphatic amino acid. It is Essential amino acid, essential in humans, meaning the body cannot synthesize it; it must be obtained from the diet. Human dietary sources are foods that contain protein, such as meats, dairy products, soy products, and beans and other legumes. It is genetic code, encoded by the codons UUA, UUG, CUU, CUC, CUA, and CUG. Leucine is named after the Greek language, Greek word for "white": ''λευκός'' (''leukós'', "white"), after its common appearance as a white powder, a property it shares with many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudomonas
''Pseudomonas'' is a genus of Gram-negative bacteria belonging to the family Pseudomonadaceae in the class Gammaproteobacteria. The 348 members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a wide range of niches and hosts. Their ease of culture ''in vitro'' and availability of an increasing number of ''Pseudomonas'' strain genome sequences has made the genus an excellent focus for scientific research; the best studied species include '' P. aeruginosa'' in its role as an opportunistic human pathogen, the plant pathogen '' P. syringae'', the soil bacterium '' P. putida'', and the plant growth-promoting '' P. fluorescens, P. lini, P. migulae'', and '' P. graminis''. Because of their widespread occurrence in water and plant seeds such as dicots, the pseudomonads were observed early in the history of microbiology. The generic name ''Pseudomonas'' created for these organisms was defined in rather vague terms by Walter Migula i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladosporium
''Cladosporium'' is a genus of fungi including some of the most common indoor and outdoor molds. Some species are endophytes or plant pathogens, while others parasitize fungi. Description Species produce olive-green to brown or black colonies, and have dark-pigmented conidia that are formed in simple or branching chains. Many species of ''Cladosporium'' are commonly found on living and dead plant material. Including Sunflowers. The spores are wind-dispersed and they are often extremely abundant in outdoor air. Indoors ''Cladosporium'' species may grow on surfaces when moisture is present. '' Cladosporium fulvum'', cause of tomato leaf mould, has been an important genetic model, in that the genetics of host resistance are understood. In the 1960s, it was estimated that the genus ''Cladosporium'' contained around 500 plant-pathogenic and saprotrophic species, but this number has since been increased to over 772 species. The genus is very closely related to black yeasts in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tomato
The tomato (, ), ''Solanum lycopersicum'', is a plant whose fruit is an edible Berry (botany), berry that is eaten as a vegetable. The tomato is a member of the nightshade family that includes tobacco, potato, and chili peppers. It originated from and was domesticated in western South America. It was introduced to the Old World by the Spanish in the Columbian exchange in the 16th century. Tomato plants are vines, largely Annual plant, annual and vulnerable to frost, though sometimes living longer in greenhouses. The flowers are able to self-fertilise. Modern varieties have been bred to ripen uniformly red, in a process that has impaired the fruit's sweetness and flavor. There are thousands of cultivars, varying in size, color, shape, and flavor. Tomatoes are attacked by many insect pests and nematodes, and are subject to diseases caused by viruses and by mildew and blight fungi. The tomato has a strong savoury umami flavor, and is an important ingredient in cuisines around ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xanthomonas
''Xanthomonas'' (from greek: ''xanthos'' – "yellow"; ''monas'' – "entity") is a genus of bacteria, many of which cause plant pathology, plant diseases. There are at least 27 plant associated ''Xanthomonas spp.'', that all together infect at least 400 plant species. Different species typically have specific host and/or tissue range and colonization strategies. Taxonomy The genus ''Xanthomonas'' has been subject of numerous taxonomic and phylogenetic studies and was first described as ''Bacterium vesicatorium'' as a pathogen of pepper and tomato in 1921. Dowson later reclassified the bacterium as ''Xanthomonas campestris'' and proposed the genus ''Xanthomonas''.''Xanthomonas'' was first described as a monotypic genus and further research resulted in the division into two groups, A and B. Later work using DNA:DNA hybridization has served as a framework for the general ''Xanthomonas'' species classification. Other tools, including multilocus sequence analysis and amplified fragmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rice
Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much less commonly, ''Oryza glaberrima'' (African rice). Asian rice was domesticated in China some 13,500 to 8,200 years ago; African rice was domesticated in Africa about 3,000 years ago. Rice has become commonplace in many cultures worldwide; in 2023, 800 million tons were produced, placing it third after sugarcane and maize. Only some 8% of rice is traded internationally. China, India, and Indonesia are the largest consumers of rice. A substantial amount of the rice produced in developing nations is lost after harvest through factors such as poor transport and storage. Rice yields can be reduced by pests including insects, rodents, and birds, as well as by weeds, and by List of rice diseases, diseases such as rice blast. Traditional rice polyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
