Resistance to Erwinia spp. in potato (Solanum tuberosum L.)

S. Allefs

Research output: Thesisexternal PhD, WU

Abstract

Blackleg is a disease of potato, <em>Solanum tuberosum</em> , which is caused by the bacteria <em>Erwinia carotovora</em> subsp. carotovora ( <em>Ecc</em> ), <em>E.c.</em> subsp. <em>atroseptica</em> ( <em>Eca</em> ) or <em>E</em> . <em>chrysanthemi (Ech). Incidence</em> of blackleg negatively affects the quality of seed potatoes. Disease control relies on phytosanitary measures aiming to reduce the spread of the pathogen. Partial resistance has been identified but exploitation of genotypic variation has been hindered by the lack of efficient and accurate methods for measuring resistance.<p>The partial resistance of 12 cultivars was studied in terms of components of resistance. Tuber tissue resistance was considered as a putative component and studied under aerobic and anaerobic conditions. Significant and reproducible differences for resistance were found, but these differences had no explanatory value in relation to resistance to blackleg in the field. However, it was found that the mother tubers of plants in the field play a role in determining field resistance but that this role for a given cultivar can not be predicted from resistance screening under laboratory conditions. Another important component of resistance was found to be located in the stem base. When stem base resistance was measured by inoculation with <em>Ech,</em> this component accounted for 58% and 65% of the variance in field experiments for resistance to <em>Eca</em> and <em>Ech,</em> respectively. Resistance of the above ground stem tissue was of minor importance in determining blackleg resistance.<p>A study on one first, and 11 second backcross populations which were derived from somatic hybrids between <em>S. tuberosum</em> and <em>S. brevidens</em> , revealed that relatively high levels of tuber tissue resistance could be found in this material. As for cultivars, no correlation was found between tuber tissue resistance and resistance to blackleg. It is doubtful whether the material is useful as a source of resistance to blackleg. In addition, attempts were undertaken to introduce resistance in potato cultivars by means of genetic transformation with constructs encoding the antibacterial peptides <em>cecropin</em> B, α-hordothionin and tachypiesin 1. Transcription of the cecropin B gene was found in transgenic plants but no expression of this peptide. This was probably a result of instability of cecropin B in potato tissue. Expression of α-hordothionin was found but the transgenic plants did not show enhanced resistance. Expression of tachypiesin 1 was detected in transgenic plants of cvs Bintje, Karnico and Kondor. Small tubers of these transgenic plants showed a slight improvement of tuber tissue resistance in a repeated experiment, especially under aerobic conditions.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
Supervisors/Advisors
  • Parlevliet, J.E., Promotor
  • Schippers, B., Promotor, External person
Award date30 May 1995
Place of PublicationS.l.
Publisher
Print ISBNs9789054853848
Publication statusPublished - 1995

Keywords

  • plants
  • pest resistance
  • disease resistance
  • solanum tuberosum
  • potatoes
  • plant diseases
  • plant pathogenic bacteria
  • erwinia
  • plant breeding

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