What is polygalacturonase gene?
Polygalacturonase (PG) is the major cell wall degrading enzyme of tomato fruit. It is developmentally regulated and is synthesised de novo in ripening fruit. Genomic clones encoding a PG gene of tomato (Lycopersicon esculentum Mill cv. Ailsa Craig) have been isolated, mapped and sequenced.
What is ethylene synthesis?
Ethylene is synthesized from S-adenosylmethionine (SAM), an activated form of methionine (Met), via 1-aminocyclopropane-1-carboxylic acid (ACC) (Yang and Hoffman 1984). The two key ethylene biosynthetic enzymes, ACC synthase (ACS) and ACC oxidase (ACO), are both encoded by multigene families.
What is the substrate for Polygalacturonase?
Substrate specificity Polygalacturonase activity was tested with different pectins and was compared with standard polygalacturonic acid (PGA) (Sigma), which was regarded to have 100% activity. The tested substrates were citrus pectin, apple pectin, xylan, glycogen, corn starch, potato starch, dextran, and CM-cellulose.
Why are desert plants especially dependent upon ABA?
Propose an explanation for why desert plants might be especially dependent upon ABA. Read This! The plants evolved in this way because the undesirable taste of the fruit protected the underdeveloped seeds, so that they would not be dispersed before they were ready.
What causes the softening of the cell wall and the breaking of sugars?
The disassembly of pectin, a major component of plant cell walls, causes cell wall degradation, which leads to an increase in softening as ripening progresses [7]. Through the loss of pectic side chains during the ripening stage, increased plant cell wall porosity enhances enzymatic cell wall-degradation activity [8] .
What is the function of the Yang cycle during ethylene biosynthesis?
Structural representation of the Yang Cycle, which functions to recycle 5′-methylthioadenosine (MTA), the by-product of ACC biosynthesis, back to methionine. The general precursor S-adenosyl-l-methionine (SAM) is shared by ethylene biosynthesis and several other pathways.
Why does pg make fruit softer?
A plant hormone that helps plant growth and helps the plant to gain energy before it can photosynthesize. A plant hormone that is a gas and helps to ripen fruits. PG (polygalacturonase) An enzyme that breaks the bonds in the fruit’s cell wall to make it softer.
Why removing or covering the tip of the coleoptile might result in a lack of positive Phototropism?
The characteristic response of plants to sunlight—growing toward the light—is called positive phototropism. Propose an explanation of why removing or covering the tip of the coleoptile might result in a lack of positive phototropism. The tip contains something (hormone) that causes growth toward the light. 6.