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One of the most important diseases of pea is caused by Pea seed-borne mosaic virus (PSbMV), which has a relatively wide host range. Since there are few varieties with resistance against the virus, and spraying insecticides is not very effective, the determination of the disease and the pathogen in the seeds is very important. Inoculum prepared from pea seeds showing typical virus symptoms caused very mild symptoms on Chenopodium amaranticolor and C. quinoa, but several chlorotic/necrotic lesions on bean (Phaseolus vulgaris) cv. Scarlet, and systemic symptoms with mosaic and curling of top leaves on bean cv. Maxidor. The detection of the virus was carried out by PCR using universal primers and virus sequence analysis. According to the phylogenetic analysis the PSbMV isolate identified in Hungary belongs to the pathotype P1 and associated with the cluster 2 isolates.

Open access
Acta Alimentaria
Authors:
Sz. Luzics
,
Á. Tóth
,
T. Barna
,
E. Szabó
,
I. Nagy
,
B. Horváth
,
I. Nagy
,
Z. Varecza
,
I. Bata-Vidács
, and
J. Kukolya

Abstract

Thermobifida alba is the mesophilic member of the Thermobifida genus, the genome and enzyme sets of which have not been described and published yet. Thermobifida strains are thermotolerant actinomycete, which possess wide sets of cellulose and hemicellulose hydrolysing enzymes. Previously, three endomannanases (Man5ATh, Man5ATc, and Man5AThf) of thermobifidas were cloned and investigated, and hereby the endomannanase of T. alba DSM 43795 is described. All four endomannanases belong to the glycoside hydrolase family 5, their sizes are around 50–55 kDa. Their structure consists of a catalytic domain and a carbohydrate binding module, while there is an interdomain linker region in-between consisting repetitive tetrapeptide motifs (eg.: PPTEPTD-Ta, PTDP-Tc, TEEP-Tf, DPGT-Th). The pH optima of Man5A enzymes from T. alba, Thermobifida halotolerans, Thermobifida cellulosilytica, and Thermobifida fusca are slightly different (6.5, 7.0, 7.5, and 8.0, respectively), however, the temperature optima of the enzymes were detected within a wider range of 65–75 °C. In this research, Man5ATa exhibited the lowest Michaelis-Menten constant (KM) (0.13 mM) on LBG-mannan substrate, while others shared similar kinetic parameters: 0.9–1.7 mM of KM. Despite the high sequence similarity of the investigated mannanases, they exhibit different temperature stability parameters. These different functional characteristics can be advantageous for industrial applications producing biologically active, oligomannan prebiotics under different conditions.

Open access