Isoliquiritigenin, a Strong nod Gene- and Glyceollin Resistance- Inducing Flavonoid from Soybean Root Exudate

Isoflavonoid signal molecules from soybean (Glycine max (L.) Merr.) seed and root exudate induce the transcription of nodulation (nod) genes in Bradyrhizobium japonicum. In this study, a new compound with symbiotic activity was isolated from soybean root exudate. The isolated 2',4',4-trihydroxychalcone (isoliquiritigenin) is characterized by its strong inducing activity for the nod genes of B. japonicum. These genes are already induced at concentrations 1 order of magnitude below those required of the previously described isoflavonoid inducers genistein and daidzein. Isoliquiritigenin is also a potent inducer of glyceollin resistance in B. japonicum, which renders this bacterium insensitive to potentially bactericidal concentrations of glyceollin, the phytoalexin of G. max. No chemotactic effect of isoliquiritigenin was observed. The highly efficient induction of nod genes and glyceollin resistance by isoliquiritigenin suggests the ecological significance of this compound, although it is not a major flavonoid constituent of the soybean root exudate in quantitative terms

Entwicklung und Niveau des Bodenreaktionszustandes und der Grundnährstoffversorgung auf dem Ackerland von ökologisch wirtschaftenden Betrieben in Mecklenburg-Vorpommern

Um Aussagen über die Entwicklung und das Niveau des Bodenreaktionszustandes und der Grundnährstoffversorgung des ökologischen Landbaus zu gewinnen, wurden die in der LUFA Rostock untersuchten Bodenproben von ökologisch wirtschaftenden Betrieben aus den Jahren 2006 bis 2013 übernommen, zu Zeitreihen zusammengestellt und ausgewertet. Gleichzeitig erfolgte ein Vergleich mit den Bodenproben aus dem konventionellen Landbau

Competitiveness and communication for effective inoculation byRhizobium, Bradyrhizobium and vesicular-arbuscular mycorrhiza fungi

After a short summary on the ecology and rhizosphere biology of symbiotic bacteria and vesicular-arbuscular (VA) mycorrhiza fungi and their application as microbial inocula, results on competitiveness and communication are summarized. Stress factors such as high temperature, low soil pH, aluminium concentrations and phytoalexins produced by the host plants were studied withRhizobium leguminosarum bv.phaseoli andRhizobium tropici onPhaseolus beans. Quantitative data for competitiveness were obtained by usinggus + (glucoronidase) labelled strains, which produce blue-coloured nodules. ForPhaseolus-nodulating rhizobia, a group specific DNA probe was also developed, which did not hybridize with more than 20 other common soil and rhizosphere bacteria. Results from several laboratories contributing to knowledge of signal exchange and communication in theRhizobium/Bradyrhizobium legume system are summarized in a new scheme, including also defense reactions at the early stages of legume nodule initiation. Stimulating effects of flavonoids on germination and growth of VA mycorrhiza fungi were also found. A constitutive antifungal compound in pea roots, -isoxazolinonyl-alanine, was characterized

Communication and signal exchange in the Rhizobium bradyrhizobium legume system

A new comprehensive communication concept in the Rhizobium/Bradyrhizobium legume symbiosis was developed. It includes a root zone specific flavonoid exudation, the differential activity of phenylpropane/acetate pathway derivatives on chemotaxis, nod-gene inducing activity and phytoalexin resistance induction on the microsymbiont side (Bradyrhizobium). Nod factor production from the microsymbiont affects the host plant in root hair curling and meristem induction. Phytoalexin production in the host plant is also an early response, however repressed to a low level after a few hours. Another strategy of the microsymbiont to overcome phytoalexin effects is degradation of phytoalexins in Rhizobium leguminosarum bv. vicieae. Competitiveness within the same infection group of the microsymbiont was studied with gus-gene fusion, using the blue coloured nodules to easily discriminate marked strains from unmarked competitors. New exopolysaccharide (EPS) mutants of Bradyrhizobium japonicum were reconstructed homologous with a DNA region to exoB gene of Rhizobium meliloti. Their clearly reduced competitiveness of nodulation, demonstrates that exopolysaccharides of Bradyrhizohium japonicum also have an important function during the early stages of this symbiotic interaction

ANALISIS MUTU ORGANOLEPTIK KOPI BUBUK ARABIKA (Coffea arabica) BITTUANG TORAJA

Kopi arabika (Coffea arabica) mempunyai mutu cita rasaterbaik dibandingkan jenis kopiyang lain, dengan ciri biji berbentuk putih kehijauan dan daun hijau tua. Secara umum,pengolahan kopi di Indonesia terdiri dari pengolahan secara kering, secara basah, dan luwak.Penelitian ini bertujuan untuk mengetahui mutu kopi arabika secara organoleptik (warna, tekstur,aroma, rasa) melalui proses pengolahan bahan baku (kering, basah, luwak). Berat biji kopiarabika untuk masing-masing perlakuan adalah 1000 gram. Setelah dilakukan prosespengolahan, biji kopi disangrai dan digiling, dilakukan analisis rendemen dan kadar air, kemudiandilakukan penyeduhan dengan air panas 500 mL. Setelah itu dilakukan pengamatan sensori(warna, tekstur, aroma, rasa). Hasil penelitian menunjukkan bahwa rendemen tertinggi padaperlakuan luwak yaitu 95,7% dan kadar air yang tertinggi pada perlakuan kering yaitu 4,86%,dimana kadar air ini sesuai dengan persyaratan Standar Nasional Indonesia (SNI) yaitu maksimal7%. Berdasarkan uji organoleptik, warna terbaik adalah perlakuan basah dengan nilai sebesar4,49; tekstur terbaik adalah perlakuan kering sebesar 3,85; dan aroma serta rasa terbaik adalahperlakuan luwak dengan nilai masing-masing sebesar 5,17 dan 3,83

Soybean Seed Extracts Preferentially Express Genomic Loci of Bradyrhizobium japonicum in the Initial Interaction with Soybean, Glycine max (L.) Merr

Initial interaction between rhizobia and legumes actually starts via encounters of both partners in the rhizosphere. In this study, the global expression profiles of Bradyrhizobium japonicum USDA 110 in response to soybean (Glycine max) seed extracts (SSE) and genistein, a major soybean-released isoflavone for nod genes induction of B. japonicum, were compared. SSE induced many genomic loci as compared with genistein (5.0 µM), nevertheless SSE-supplemented medium contained 4.7 µM genistein. SSE markedly induced four predominant genomic regions within a large symbiosis island (681 kb), which include tts genes (type III secretion system) and various nod genes. In addition, SSE-treated cells expressed many genomic loci containing genes for polygalacturonase (cell-wall degradation), exopolysaccharide synthesis, 1-aminocyclopropane-1-carboxylate deaminase, ribosome proteins family and energy metabolism even outside symbiosis island. On the other hand, genistein-treated cells exclusively showed one expression cluster including common nod gene operon within symbiosis island and six expression loci including multidrug resistance, which were shared with SSE-treated cells. Twelve putatively regulated genes were indeed validated by quantitative RT-PCR. Several SSE-induced genomic loci likely participate in the initial interaction with legumes. Thus, these results can provide a basic knowledge for screening novel genes relevant to the B. japonicum- soybean symbiosis