Knowledge about Sphagnum-associated microbial communities, their structure and their origin is important to understand and maintain climate-relevant Sphagnum-dominated bog ecosystems. We studied bacterial communities of two cosmopolitan Sphagnum species, which are well adapted to different abiotic parameters (Sphagnum magellanicum, which are strongly acidic and ombrotrophic, and Sphagnum fallax, which are weakly acidic and mesotrophic), in three Alpine bogs in Austria by a multifaceted approach. Great differences between bacterial fingerprints of both Sphagna were found independently from the site. This remarkable specificity was confirmed by a cloning and a deep sequencing approach. Besides the common Alphaproteobacteria, we found a discriminative spectrum of bacteria; although Gammaproteobacteria dominated S. magellanicum, S. fallax was mainly colonised by Verrucomicrobia and Planctomycetes. Using this information for fluorescent in situ hybridisation analyses, corresponding colonisation patterns for Alphaproteobacteria and Planctomycetes were detected. Bacterial colonies were found in high abundances inside the dead big hyalocytes, but they were always connected with the living chlorocytes. Using multivariate statistical analysis, the abiotic factors nutrient richness and pH were identified to modulate the composition of Sphagnum-specific bacterial communities. Interestingly, we found that the immense bacterial diversity was transferred via the sporophyte to the gametophyte, which can explain the high specificity of Sphagnum-associated bacteria over long distances. In contrast to higher plants, which acquire their bacteria mainly from the environment, mosses as the phylogenetically oldest land plants maintain their bacterial diversity within the whole lifecycle.

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SummaryThirty endophytic bacteria were isolated from various plant species growing near Saint‐Petersburg, Russia. Based on a screening for various traits, including plant‐beneficial properties and DNA fragment patterns, potential siblings were removed. The remaining isolates were taxonomically identified using 16S rDNA sequences and potential human and plant pathogens were removed. The remaining strains were tested for their ability to promote radish root growth and to protect tomato plants against tomato foot and root rot. One strain, Bacillus subtilis HC8, isolated from the giant hogweed Heracleum sosnowskyi Manden, significantly promoted plant growth and protected tomato against tomato foot and root rot. Metabolites possibly responsible for these plant‐beneficial properties were identified as the hormone gibberellin and (lipo)peptide antibiotics respectively. The antibiotic properties of strain HC8 are similar to those of the commercially available plant‐beneficial strain Bacillus amyloliquefaciens FZB42. However, thin layer chromatography profiles of the two strains differ. It is speculated that endophytes such as B. subtilis HC8 contribute to the fast growth of giant hogweed.

In a previous study (Malfanova et al. in Microbial Biotech 4:523–532, 2011), we described the isolation and partial characterization of the biocontrol endophytic bacterium B. subtilis HC8. Using thin-layer chromatography, we have detected several bioactive antifungal compounds in the methanolic extract from the acid-precipitated supernatant of HC8. In the present study, we have further analyzed this methanolic extract using liquid chromatography-mass spectrometry. Based on the comparison of retention times and molecular masses with those of known antifungal compounds, we identified three families of lipopeptide antibiotics. These include four iturins A having fatty acyl chain lengths of C14 to C17, eight fengycins A (from C14 to C18 and from C15 to C17 containing a double bond in the acyl chain), four fengycins B (C15 to C18), and five surfactins (C12 to C16). Evaluation of the antifungal activity of the isolated lipopeptides showed that fengycins are the most active ones. To our knowledge, this is the first report of an endophytic Bacillus subtilis producing all three major families of lipopeptide antibiotics containing a very heterogeneous mixture of homologues. The questions remain open which of these lipopeptides (1) are being produced during interaction with the plant and (2) are contributing to the biocontrol activity of HC8.

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ВВЕДЕНИЕÇíà÷èòåëüíîå óâåëè÷åíèå èñïîëüçîâàíèÿ àãðîõèìèêàòîâ â ïåðèîä ñ 1960 ãîäà ïî 2000 ãîä â ðåçóëüòàòå èíòåíñèôèêàöèè ñåëüñêîõîçÿé-ñòâåííîãî ïðîèçâîäñòâà ïðèâåëî ê çíà÷èòåëüíîìó èñòîùåíèþ åñòå-ñòâåííîãî ïîòåíöèàëà ïëîäîðîäèÿ ïî÷â, óõóäøåíèþ êà÷åñòâà âîäû è âîçäóõà, ñíèaeåíèþ êà÷åñòâà îïðåäåëåííûõ âèäîâ ñåëüñêîõîçÿéñòâåí-íîé ïðîäóêöèè [23].  ñâÿçè ñ ýòèì â íàñòîÿùåå âðåìÿ íàáëþäàåòñÿ èçìåíåíèå îñíîâíîé êîíöåïöèè ñåëüñêîãî õîçÿéñòâà îò èíòåíñèâíîãî ê óñòîé÷èâîìó, ýêîëîãè÷åñêè-îðèåíòèðîâàííîìó. Îäíèì èç ïåðñïåê-òèâíûõ íàïðàâëåíèé ñîâðåìåííîãî çåìëåäåëèÿ ÿâëÿåòñÿ èñïîëüçîâà-íèå ïîòåíöèàëà ïîëåçíîé ïî÷âåííîé ìèêðîôëîðû. Ñèìáèîòè÷åñêèå ìèêðîîðãàíèçìû èãðàþò âàaeíóþ ðîëü â ðàçâèòèè ðàñòåíèé, îáåñïå-÷èâàÿ èõ ìèíåðàëüíîå ïèòàíèå, çàùèòó îò ïàòîãåíîâ è âðåäèòåëåé, àäàïòàöèþ ê ðàçëè÷íûì ñòðåññàì [8,9].Íàèáîëåå âàaeíîå ýêîëîãè÷åñêîå è ïðàêòè÷åñêîå çíà÷åíèå èìåþò ýíäîñèìáèîòè÷åñêèå ñèñòåìû: áîáîâî-ðèçîáèàëüíûé ñèìáèîç è àð-áóñêóëÿðíàÿ ìèêîðèçà (ÀÌ). Ñèìáèîç ñ êëóáåíüêîâûìè áàêòåðèÿìè (ÊÁ) ðîäîâ Rhizobium, Sinorhizobium, Bradyrhizobium è äð. ïîçâîëÿåò áîáîâûì ðàñòåíèÿì ðàçâèâàòüñÿ â óñëîâèÿõ äåôèöèòà ñâÿçàííîãî àçîòà, òîãäà êàê âçàèìîäåéñòâèå ñ ÀÌ ãðèáàìè, ôèëà Glomeromycota [21], îáåñïå÷èâàåò àññèìèëÿöèþ òðóäíîðàñòâîðèìûõ ôîñôàòîâ è äðóãèõ ïèòàòåëüíûõ ýëåìåíòîâ ïî÷âû. Èíîêóëÿöèÿ áîáîâûõ êóëüòóð ÊÁ ïðèâîäèò ê ñóùåñòâåííîìó óâåëè÷åíèþ óðîaeàÿ (îò 15 % äî 60 %), à òàêaeå ê ôèêñàöèè 40-450 êã àçîòà íà ãåêòàð çà ñåçîí [11]. Ðåçóëü-òàòîì øèðîêîãî ïðèìåíåíèÿ áèîïðåïàðàòîâ íà îñíîâå ÊÁ ÿâëÿåòñÿ ñíèaeåíèå ïðèìåíåíèÿ àçîòíûõ óäîáðåíèé è àêêóìóëÿöèè íèòðàòîâ ðàñòåíèÿìè, ïî÷âîé è âîäîé. Ìèêîðèçàöèÿ âåäåò ê óëó÷øåíèþ ðîñòà ðàñòåíèé, îäíàêî øèðîêîå èñïîëüçîâàíèå ýòîãî ñèìáèîçà îãðàíè÷åíî ñëîaeíîñòüþ ïðèãîòîâëåíèÿ ïðåïàðàòîâ ìèêîðèçíûõ ãðèáîâ. Áîáî-âî-ðèçîáèàëüíûé è ÀÌ ñèìáèîçû òàêaeå ïðåäîõðàíÿþò ïî÷âû îò èñòîùåíèÿ è ïîääåðaeèâàþò áèîëîãè÷åñêîå ðàçíîîáðàçèå ðàñòèòåëü-íûõ ñîîáùåñòâ [12,16]. Ýòè äâà ñèìáèîçà ñèëüíî ðàçëè÷àþòñÿ ïî ôèçèîëîãèè, ìîðôîëîãèè è ñïåöèôè÷íîñòè âçàèìîäåéñòâèÿ. Òåì íå ìåíåå ó áîáîâûõ ðàñòåíèé âûÿâëåíà åäèíàÿ ñèñòåìà ðàçâèòèÿ ýòèõ ñèìáèîçîâ, êîòîðàÿ èìååò ìíîãî îáùèõ ýëåìåíòîâ ñ ñèñòåìàìè çàùè-òû ðàñòåíèé îò ïàòîãåíîâ è ÿâëÿåòñÿ îñíîâîé ðàñòèòåëüíî-ìèêðîáíî-ãî ýâîëþöèîííîãî êîíòèíóóìà [8,9]. Îäíàêî â ëèòåðàòóðå îïèñàíî

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