This protocol is used to induce transgenic roots on soybean to study the function of genes required in biological processes of the root. Young seedlings with unfolded cotyledons are infected at the cotyledonary node and/or hypocotyl with Agrobacterium rhizogenes carrying the gene construct to be tested and the infection sites are kept in an environment of high humidity. When the emerged hairy roots can support the plants, the main roots are removed and the transgenic roots can be tested. Using this method, almost 100% of the infected plants form hairy roots within 1 month from the start of the experiments.
Notes on 113 fungal taxa are compiled in this paper, including 11 new genera, 89 new species, one new subspecies, three new combinations and xx reference specimens. A wide geographic and taxonomic range of fungal taxa are detailed. In the Ascomycota the new genera Angustospora (Testudinaceae), Camporesia (Xylariaceae), Clematidis, Crassiparies (Pleosporales genera incertae sedis), Farasanispora, Longiostiolum (Pleosporales genera incertae sedis), Multilocularia (Parabambusicolaceae), Neophaeocryptopus (Dothideaceae), Parameliola (Pleosporales genera incertae sedis), and Towyspora (Lentitheciaceae) are introduced. Newly introduced species are Angustospora nilensis, Aniptodera
The nodule autoregulation receptor kinase (GmNARK) of soybean (Glycine max) is essential for the systemic autoregulation of nodulation. Based on quantitative reverse-transcriptase polymerase chain reaction, GmNARK is ex-pressed to varying levels throughout the plant; the transcript was detected at high levels in mature leaves and roots but to a lesser extent in young leaves, shoot tips, and nodules. The transcript level was not significantly affected by Bradyrhizobium japonicum during the first week following inoculation. In addition, the activities of the promoters of GmNARK and Lotus japonicus HARI, driving a beta-glucuronidase (GUSPlus) reporter gene, were examined in stably transformed L. japonicus and transgenic hairy roots of soybean. Histochemical GUS activity in L. japonicus plants carrying either a 1.7-kb GmNARKpr::GUS or 2.0-kb LjHAR1pr::GUS construct was clearly localized to living cells within vascular bundles, especially phloem cells in leaves, stems, roots, and nodules. Phloem-specific expression also was detected in soybean hairy roots carrying these constructs. Our study suggests that regulatory elements required for the transcription of these orthologous genes are conserved. Moreover, rapid amplification of 5' cDNA ends (5' rapid amplification of cDNA ends) revealed two major transcripts of GmNARK potentially originating from two TATA boxes. Further analysis of the GmNARK promoter has confirmed that these two TATA boxes are functional. Deletion analysis also located a region controlling phloem-specific expression to a DNA sequence between 908 bp and 1.7 kb upstream of the translation start site of GmNARK.
Three orchid genera, Paphiopedilum, Cymbidium, and Dendrobium, are among the most heavily traded ornamental plants in Thailand. In this study, 27 isolates of Rhizoctonia-like fungi were isolated from root sections of mature orchids in the three orchid genera, collected from diverse horticultural settings in Chiang Mai and Chiang Rai provinces of Thailand. Fungal identification was done by the morphological characterization, the comparison of the internal transcribed spacer and 5.8S ribosomal DNA sequences, and the phylogenetic analysis. Epulorhiza repens was found to be the most common species found in the roots of various species of all three orchid genera, whereas Epulorhiza calendulina-like isolates were strictly found in the roots of Paphiopedilum species. We have also isolated and described an anamorph of Tulasnella irregularis, four new anamorphic species in the genus Tulasnella, and a new anamorphic species in the family Tulasnellaceae. Our study provides information on diversity of root-associated fungi of the orchid genera and at the sampling sites that were rarely addressed in the previous studies.
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