Potential new genes for resistance to Mycosphaerella graminicola identified in Triticum aestivum x Lophopyrum elongatum disomic substitution lines.

Lophopyrum species carry many desirable agronomic traits, including disease resistance, which can be transferred towheat by interspecific hybridization. To identify potentially new genes for disease and insect resistance carried by individual Lophopyrum chromosomes, 19 of 21 possible wheat cultivar Chinese Spring 9 Lophopyrum elongatum disomic substitution lines were tested for resistance to barley yellow dwarf virus (BYDV), cereal yellow dwarf virus (CYDV), the Hessian fly Mayetiola destructor, and the fungal pathogens Blumeria graminis and Mycosphaerella graminicola (asexual stage: Septoria tritici). Low resistance to BYDV occurred in some of the disomic substitution lines, but viral titers were significantly higher than those of two Lophopyrum species tested. This suggested that genes on more than one Lophopyrum chromosome are required for complete resistance to this virus. A potentially new gene for resistance to CYDV was detected on wheatgrass chromosome 3E. All of the substitution lines were susceptible to Mayetiola destructor and one strain of B. graminis. Disomic substitution lines containing wheatgrass chromosomes 1E and 6E were significantly more resistant to M. graminicola compared to Chinese Spring. Although neither chromosome by itself conferred resistance as high as that in the wheatgrass parent, they do appear to contain potentially new genes for resistance against this pathogen that could be useful for future plant-improvement programs

A review of the current literature on management of halitosis.

Contains fulltext : 69098.pdf (publisher's version ) (Closed access)Halitosis is an unpleasant or offensive odour, emanating from the oral cavity. In approximately 80% of all cases, halitosis is caused by microbial degradation of oral organic substrates. Major degradation products are volatile sulphur-containing compounds. In this review, the available management methods of halitosis and their effectiveness and significance are presented and discussed. Undoubtedly, the basic management is mechanically reducing the amount of micro-organisms and substrates in the oral cavity. Masking products are not, and antimicrobial ingredients in oral healthcare products are only temporary effective in reducing micro-organisms or their substrates. Good short-term results were reported with chlorhexidine. Triclosan seems less effective, essential oils and cetylpyridinium chloride are only effective up to 2 or 3 h. Metal ions and oxidizing agents, such as hydrogen peroxide, chlorine dioxide and iminium are active in neutralizing volatile sulphur-containing compounds. Zinc seems to be an effective safe metal at concentrations of at least 1%. The effectiveness of active ingredients in oral healthcare products is dependent on their concentration and above a certain concentration the ingredients can have unpleasant side effects. Tonsillectomy might be indicated if (i) all other causes of halitosis are managed properly; (ii) halitosis still persists and (iii) crypts in tonsils are found to contain malodorous substrates