Xin Wang

The stability of gut microbiota is essential for the host's health. Parabacteroides spp., core members of the human gut microbiota, have an average abundance of 1.27% in humans of 12 populations. Parabacteroides have recently been reported to have a close relationship with host health (e.g. metabolic syndrome, inflammatory bowel disease and obesity). Parabacteroides have the physiological characteristics of carbohydrate metabolism and secreting short chain fatty acids. However, antimicrobial resistance of Parabacteroides to antibiotics (such as clindamycin, moxifloxacin and cefoxitin) should not be ignored. In this review, we primarily focus on Parabacteroides distasonis, Parabacteroides goldsteinii, Parabacteroides johnsonii and Parabacteroides merdae and discuss their relationships with host disease, diet and the prevention or induction of diseases. Pa. distasonis and Pa. goldsteinii may be viewed as potential next generation probiotic candidates due to their protective effects on inflammation and obesity in mice. We also discuss the potential therapeutic application of Parabacteroides spp. in maintaining host-intestine homeostasis.

We present the 1.06 Gb sequenced genome of Gastrodia elata, an obligate mycoheterotrophic plant, which contains 18,969 protein-coding genes. Many genes conserved in other plant species have been deleted from the G. elata genome, including most of those for photosynthesis. Additional evidence of the influence of genome plasticity in the adaptation of this mycoheterotrophic lifestyle is evident in the large number of gene families that are expanded in G. elata, including glycoside hydrolases and urease that likely facilitate the digestion of hyphae are expanded, as are genes associated with strigolactone signaling, and ATPases that may contribute to the atypical energy metabolism. We also find that the plastid genome of G. elata is markedly smaller than that of green plant species while its mitochondrial genome is one of the largest observed to date. Our report establishes a foundation for studying adaptation to a mycoheterotrophic lifestyle.