Publications

4641

South Florida (USA) has a subtropical to tropical climate with an extensive and diverse coastline that supports the growth of benthic cyanobacterial mats (BCMs). These BCMs are widespread and potentially house numerous bioactive compounds; however, the extent of the cyanobacterial diversity within these mats remains largely unknown. To elucidate this diversity, BCMs from select locations in South Florida were sampled and isolated into unicyanobacterial cultures for morphological and molecular studies. Phylogenetic relationships of isolated taxa were assessed using the markers 16S rRNA and 16S‐23S rRNA ITS by both maximum likelihood and Bayesian inference. We propose Affixifilum gen. nov. based on morphological characteristics and the 16S rRNA phylogeny. Two species are included: Affixifilum granulosum comb nov. (=Neolyngbya granulosa) found in Brazil and Florida (USA) and A. floridanum sp. nov. Several other features, including pair‐wise distance of 16S rRNA and 16S‐23S rRNA ITS, 16S‐23S rRNA ITS secondary structure, morphology, and ecology, provide support for Affixifilum. We also propose the transfer of Lyngbya regalis to Neolyngbya as N. regalis comb. nov. and include the description of one novel species, N. biscaynensis sp. nov.

AbstractApple proliferation disease is caused by the phloem-dwelling bacterium ‘CandidatusPhytoplasma mali’, inducing morphological changes in its host plant apple, such as witches’ broom formation. Furthermore, it triggers physiological alterations like emission of volatile organic compounds or phytohormone levels in the plant. In our study, we assessed phytoplasma-induced changes in the phloem by sampling phloem sap from infected and non-infected apple plants. In infected plants, the soluble sugar content increased and the composition of phloem metabolites differed significantly between non-infected and infected plants. Sugar and sugar alcohol levels increased in diseased plants, while organic and amino acid content remained constant. As ‘Ca. P. mali’ is vectored by the phloem-feeding insectCacopsylla picta(Foerster, 1848), we assessed whether the insect–plant interaction was affected by ‘Ca. P. mali’ infection of the common host plantMalus domesticaBorkh. Binary-choice oviposition bioassays between infected and non-infected apple leaves revealedC. picta’s preference for non-infected leaves. It is assumed and discussed that the changes in vector behavior are attributable to plant-mediated effects of the phytoplasma infection.