Stronger induction of callose deposition in XXXX by Russian @entity3505 aphid than bird cherry-oat aphid is not associated with differences in callose synthase or beta-1,3-glucanase transcript abundance.

@entity71108 @entity2247 @entity27106 @entity24194 @entity277 @entity3505
The effects of @entity277 by the bird cherry-oat aphid (BCA), (Rhopalosiphum padi L) and the Russian @entity3505 aphid (RWA) (Diuraphis noxia Mordvilko) on callose deposition and transcription of genes related to @entity71108 accumulation were investigated in @entity2247 ( @entity2247 . cv. Clipper). The BCA, which gives no visible symptoms, induced very limited callose deposition, even after 14 days of @entity277 . In contrast, RWA, which causes @entity24194 , white and yellow streaking and leaf rolling, induced callose accumulation already after 24 h in longitudinal leaf veins. The deposition was pronounced after 72 h, progressing during 7 and 14 days of @entity277 . In RWA-infested source leaves, callose was also induced in longitudinal veins basipetal to the aphid-infested tissue, whereas in sink leaves, more callose deposition was found above the feeding sites. Eight putative callose synthase genes were identified in a database search, of which seven were expressed in the leaves, but with similar transcript accumulation in control and aphid-infested tissue. Five out of 12 examined beta-1,3-glucanases were expressed in the leaves. All five were upregulated in RWA-infested tissue, but only two in BCA-infested tissue, and to a lesser extent than by RWA. The results suggest that callose accumulation may be partly responsible for the symptoms resulting from @entity27106 and that a callose-inducing signal may be transported in the phloem. Furthermore, it is concluded that the absence of callose deposition in BCA-infested leaves is not because of a stronger upregulation of callose-degrading beta-1,3-glucanases in this tissue, as compared to RWA-infested leaves.
