Furch, Alexandra C. U.

Jelkmann, Wilhelm

Schneider, Bernd

Seemüller, Erich

Wensing, Annette

Zikeli, Kerstin

English

JKI Open Journal Systems (Julius Kühn-Institut)

10th Young Scientists Meeting, Siebeldingen, Germany, November 08-10, 2017 Zikeli et al. AAA+ ATPase AP460  –  A virulence factor of apple proliferation disease? Kerstin Zikeli1, Erich Seemüller1, Bernd Schneider2, Alexandra C. U. Furch3, Annette Wensing1 and Wilhelm Jelkmann1 1Julius Kühn-Institut, Institute for Plant Protection in Fruit Crops and Viticulture, Dossenheim 2Thünen Institut, Institute of Forest Genetics, Waldsieversdorf 3Friedrich Schiller University, Institute of General Botany and Plant Physiology, Jena E-mail of corresponding author: kerstin.zikeli@julius-kuehn.de´Candidatus Phytoplasma mali`, a wall-less phytopathogenic bacterium of the class Mollicutes and the agent of apple proliferation (AP) disease, causes specif-ic symptoms (undersized fruits, witches’-brooms, rosetting, enlarged stipules) and nonspecific symptoms (foliar reddening, yellowing, stunting, decline) on apple plants. ´Ca. P. mali` colonizes phloem sieve elements inducing impairment of phloem function (e.g. callose deposition on sieve plates and phloem necrosis).  However, symptom expression of AP disease is highly variable, ranging from non-symptomatic to mildly, moderately and severely affected trees. Additionally, differences in disease development of infected trees (no symptoms at all, tem-porary or permanent recovery) weremonitored in long-term observations. These variations in severity and variabil-ity of symptom expression are due to differences in the virulence of AP phytoplasma accessions (phytoplasma population in a tree). They are pheno-typically classified into avirulent, mildly, moderately or severely virulent. Molecu-lar analyses of AAA+ (ATPases Associat-ed with various cellular Activities) protein genes from infected trees of different symptom expression revealed the exist-ence of single and multiple strain acces-sions. Multiple infections are usually composed of differently virulent strains and shifts in the population may alter symptomatology. This research focuses on the membrane-associated AAA+ ATPase AP460. Since virulence-specific, as well as suppression-related clustering, was previously identified in the AP460 gene, there is indication that AP460 plays a significant role in phytoplasma pathogenicity. The current study exam-ined 147 full-length deduced AP460 pro-tein sequences of single- and multiple-strain accessions of different virulence. In sequence alignments two relevant regions were detected: region 1 in the N-terminal part possessed conserved substitutions associated with suppres-sion of virulence. The more diverse re-gion 2 in the C-terminus contained con-served substitutions, not only associatedwith two different groups of virulencebut also with suppression of virulence.Three of these suppression-related sub-stitutions, occuring next to key residuesof ATPase motifs, seem to affect ATPasefunction. Membrane topology predictionprograms (Phobius, PolyPhobius) indi-cate an extracellular C-tail orientation ofAP460, essential for being a virulencefactor. An immunohistochemical locali-zation procedure will be employed forconfirming the predicted orientation. Apurified recombinant C-terminally 6xHis-tagged AP460-ΔTM protein(transmembrane do-main deleted) willbe used as an antigen to generate poly-clonal antisera.80 Berichte aus dem Julius Kühn-Institut 192

AAA+ ATPase AP460 – A virulence factor of apple proliferation disease?

https://ojs.openagrar.de/index.php/BerichteJKI/article/download/8611/7896

AAA+ ATPase AP460 – A virulence factor of apple proliferation disease?

Abstract

Similar works

Full text

Available Versions

JKI Open Journal Systems (Julius Kühn-Institut)