Plant Pathology - Study Mode
[#336] Which toxin was first isolated in pure form?
Correct Answer
(B) Tabtoxin
Explanation
Solution: Tabtoxin was first isolated in pure form. Tabtoxin, also known as wildfire toxin, is a simple monobactam phytotoxin produced by Pseudomonas syringae. It is the precursor to the antibiotic tabtoxinine β-lactam (TBL). Tabtoxin is a dipeptide precursor to the biologically active form of TBL, differing by having an extra threonine attached by a peptide bond to the C terminus. Tabtoxin resistance protein (TTR) is an enzyme that catalyzes the acetylation of TBL, rendering tabtoxin-producing pathogens tolerant to their phytotoxins.
[#337] Meiosis occurs in
Correct Answer
(D) Spore mother cells
Explanation
Solution: Meiosis occurs in Spore mother cells. Vascular plants produce cells called spore mother cells since they will give rise to spores in spore cases (sporangia). Spore mother cells are usually surrounded, during development, by a special nutritive tissue. In the more primitive groups, each sporangium holds many mother cells.
[#338] 'Little leaf' of brinjal is caused by a
Correct Answer
(D) Mycoplasma
Explanation
Solution: 'Little leaf' of brinjal is caused by a Mycoplasma. Little leaf of Brinjal It is caused by Mycoplasma, It's transmitted by Leaf-hopper. The disease is caused by a plant pathogenic mollicute, Phytoplasma and is transmitted by the insect vector, Hishimonus phycitis which belongs to the group of leafhoppers. Management of the insect vector using insecticides and cultivation of resistant varieties is the principal means of management of the disease.
[#339] Genome of mycoviruses are
Correct Answer
(B) ds RNA
Explanation
Solution: The genome of mycoviruses is ds RNA. Mycoviruses have double-stranded (ds) or single-stranded (ss) RNA genomes. Mycoviruses are a diverse group that includes ssRNA, dsRNA, and ssDNA viruses, with or without a protein capsid, as well as with a complex envelope. Most mycoviruses are transmitted by cytoplasmic interchange and are thought to lack an extracellular phase in their infection cycle.
[#340] Cytoplasmic inheritance is governed by
Correct Answer
(D) All of these
Explanation
Solution: Cytoplasmic inheritance is governed by Cytoplasmic DNA, Mitochondrial DNA and Plasmid. Cytoplasmic inheritance is the transmission of genes that occur outside the nucleus. It is found in most eukaryotes and is commonly known to occur in cytoplasmic organelles such as mitochondria and chloroplasts or from cellular parasites like viruses or bacteria. The factors governing the cytoplasmic inheritance are called plasmon or plasmogenes, which are present in the chloroplasts (cp-DNA) or mitochondria (mt-DNA).