000			02266nam a22003257a 4500
001			G62265
003			MX-TxCIM
005			20250312104549.0
008			250312s1989||||xxu||||| |||| 00| 0 eng d
040			_aMX-TxCIM
041			_aeng
090			_aLook under author name
100	1		_aAlam, K.B.
245	1	0	_aGenetic regulation of host-selective toxin production: _b Characterization of a necrosis minus mutant of Pyrenophora tritici-repentis (died.) Drech. which has lost the ability to produce host-selective toxins in wheat
260			_aColumbia, MO (USA) : _bUniversity of Missouri-Columbia, _c1989
300			_a128 pages
340			_aPrinted
500			_aThesis (Ph. D)
520			_aPyrenophora tritici-repentis (Died.) Drech. strain mok1 (wild type) produces typical tan-spot symptoms on wheat (Triticum aestivum L. em Thell.) leaves. Strain mok2 (a naturally occurring mutant) was isolated from fleck type symptoms on wheat leaves infected with mok1. The two strains are easily distinguished by colony appearance, growth and sporulation on eight different media. Filtrates from cultures of the two strains contain chromatographically indistinguishable toxic components which cause the host-selective formation of tan-spot symptoms on wheat leaves. Quantitative leaf necrosis, ion leakage and E. coli inhibition assays indicate that approximately the same amount of toxin is formed in culture by both strains. Extracts of wheat leaf infected with mok1 (but not mok2) contain the same toxic component(s) found in culture filtrates. Strain mok2 is not an auxotrophic mutant and grows as well or better than strain mok1 in leaves of a susceptible cultivar of wheat (TAM 107). It appears that strain mok2 has retained the genes for synthesis of the host selective toxin but has lost genetic information necessary for toxin gene expression in host tissue.
546			_aEnglish
595			_aTC
650		7	_aPlant diseases _2AGROVOC _91206
650		7	_aPyrenophora tritici-repentis _2AGROVOC _92707
650		7	_aToxins _2AGROVOC _916995
650		7	_91296 _aTriticum aestivum _2AGROVOC
650		7	_aWheat _2AGROVOC _91310
650		7	_aHost Pathogen Relations _2AGROVOC _98638
650		7	_aGene Expression _2AGROVOC _98835
942			_cTH _2ddc
999			_c41167 _d41167