Warrick R Nelson | Search bioRxiv

bioRxiv2016

Transplanting as a means to enhance crop security of fodder beet

Fodder beet has become a popular winter feed for all stock classes in New Zealand. However, poor crop establishment frequently leads to either significant loss in yield, through below-target plant populations, weed competition, or crop failure. This study demonstrates that establishing the crop from transplants, common in the vegetable industry, is one way to achieve a uniform plant population and reduce weed competition through early establishment of canopy cover. The most significant effect of transplant establishment is that the target plant population is readily achieved.

Plant Biology↗

bioRxiv2015

Intragenomic homogeneity on Liberibacter 16S rDNA confirms phylogeny and explains ecological strategy

Three of the five currently recognized \"Candidatus Liberibacter\" spp., \"Ca. L. asiaticus\" (Las), \"Ca. L. americanus\" (Lam) and \"Ca. L. solanacearum\", and the newly erected genus Liberibacter species, L. crescens (Lcr), have had their genomes sequenced. In all four cases there are three homogeneous copies of the 16S rRNA gene, one present as the reverse complement of the other two. 16S intragenic homogeneity is common within the -Proteobacteria. The presence of three 16S rRNA copies indicates an advantage for a rapid response of population increase to favourable growth conditions. The metabolic cost of carrying multiple copies is avoided during periods of low cellular activity as this situation occurs at low temperatures, for example overwintering in deciduous plants or in a dormant insect host.\n\nA large insertion in the 16S rDNA sequence of three species compared to the other three species indicates a dichotomy in the Liberibacter genus and provides a phylogenetic signal of closeness to the proximal node within the Rhizobiaceae. In spite of similar symptoms in Citrus crops associated with Lam and Las infections, these species belong on either side of this dichotomy, thus confirming Lam as phylogenetically closer to the proximal node than Las.

Microbiology↗