TaUBA, a UBA domain-containing protein in wheat (Triticum aestivum L.), is a negative regulator of salt and drought stress response in transgenic Arabidopsis.

KEY MESSAGE: TaUBA functions as a negative regulator of salt and drought stress response in transgenic Arabidopsis, either the UBA domain or the zinc finger domain is crucial for TaUBA's function. TaUBA (DQ211935), which is a UBA domain-containing protein in wheat, was cloned and functionally characterized. Southern blot suggested that TaUBA is a low copy gene in common wheat. qRT-PCR assay showed that the expression of TaUBA was strongly induced by salt and drought stress. When suffering from drought and salt stresses, lower proline content and much higher MDA content in the TaUBA overexpressors were observed than those of the wild-type control, suggesting TaUBA may function as a negative regulator of salt and drought stress response in plants. To study whether the UBA domain or the zinc finger domain affects the function of TaUBA, TaUBAΔUBA (deletion of UBA domain) and TaUBA-M (Cys464Gly and Cys467Gly) overexpression vectors were constructed and transformed into Arabidopsis. Upon drought and salt stresses, the TaUBAΔUBA-and TaUBA-M-overexpressed plants accumulated much more proline and lower MDA than the wild-type control, the TaUBA-overexpressors lost water more quickly than TaUBAΔUBA-and TaUBA-M-overexpressed plants as well as the wild-type control, suggesting that overexpression of TaUBAΔUBA or TaUBA-M improved the drought and salt tolerance of transgenic Arabidopsis plants and the possibility of ubiquitination role in the regulation of osmolyte synthesis and oxidative stress responses in mediating stress tolerance. qRT-PCR assay of stress-related genes in transgenic plants upon drought and salt stresses suggested that TaUBA may function through down-regulating some stress related-transcription factors and by regulating P5CSs to cope with osmotic stress.

[Progresses on Neandertal genomics].

Neandertal is our closest known relative and also an archaic hominid reserving the richest fossils. Whether the Neandertals exchanged their DNA with modern human or not is a matter of debate on the modern human origin. The progresses on the mitochondrial and nuclear genomes of Neandertals in recent years were reviewed in this paper. Recent study has revealed possible genetic contribution of Neandertals to the modern human to some extent, which arose the rethinking of modern human origin. The experiences gained in the research on Neandertals will benefit the study on archaic hominids, unravel the mystery of modern human origin, and enrich the relative theoretical systems in evolutionary biological field.