Potential role of the gymnosperm microbiome in a changing climate

植物微生物组，即定植于植物组织内外的微生物，已被证明对植物的生长发育有很大的影响。这些微生物代表了生命的所有三个领域，真核生物，特别是真菌，细菌和古细菌，或简称古细菌。虽然土壤和植物外部组织定殖微生物已经被深入研究，但植物内部组织定殖微生物只属于细菌和真菌，它们的特性和对植物生长发育的影响已经被表征，包括许多裸子植物物种。然而，关于古生菌成员的研究很少。近年来，利用基因鉴定和生物信息学的研究结果表明，古细菌的一些成员不仅在植物组织内部定植，而且通过生长素的生物合成、增加营养供应和抵抗非生物（特别是氧化和渗透）胁迫与植物相互作用。也有一些证据表明植物和古生菌有一定程度的植物特异性。古细菌的功能特征揭示了与真菌相互作用的遗传能力，以及在碳和氮循环中发挥重要作用，例如CO2和N2固定。这些事实揭示了古细菌在大多数植物和树木中的重要作用，但尚未被观察到。随着气候变化已经在北半球的夏季变得更加温暖和干燥，裸子植物微生物群的潜在改善作用可能对裸子植物在变化的环境条件下的生长和生存非常重要。结合分子和培养技术，我建议(I)继续评估植物组织外部和内部定植细菌在裸子植物生长发育中的作用；（ii）利用分子技术提供裸子植物生长和发育过程中外部和/或内部植物组织定植古细菌的发生和潜在功能的第一个证据；（iii）尝试第一个从任何植物中分离和培养定植古生菌的外部和/或内部植物组织；（iv）评估外部和内部植物定植细菌、真菌和古细菌（如果有的话）对裸子植物在气候变暖的压力环境条件下生长和发育的相互作用。这些压力条件将包括高温、干旱和营养剥夺，研究将在受控环境下进行。这项工作将首次评估古细菌在裸子植物生长发育中的发生和作用。此外，这项工作可能会导致首次从任何植物物种的外部和/或内部组织中分离出古菌菌株，并评估细菌，真菌和古菌在胁迫条件下对裸子植物生长的相互作用。

The plant microbiome, i.e., microorganisms that colonize internal and external plant tissues, has been shown to be very influential on plant growth and development. These microorganisms represent all three domains of life, the Eukarya, particularly the fungi, the Bacteria and the Archaeabacteria, or Archaea for short. While soil and external plant tissue colonizing microbes have been studied intensively, internal plant tissue colonizing microbes belongingj only to the bacteria  and fungi have been characterized with respect to their identity and effects on plant growth and development, including many gymnosperm species. However, very little work has been reported on members of the Archaea. Recently, using gene identification and bioinformatics, there is tantalizing evidence to suggest that some members of the Archaea not only colonize internal plant tissues, but also interact with plants by auxin biosynthesis, increasing nutrient supply, and protection against abiotic (especially oxidative and osmotic) stress. There is also some evidence for a degree of plant specificity regarding plants and Archaea. Functional signatures of Archaea reveal the genetic capacity for the interplay with fungi as well as playing an important role in the carbon and nitrogen cycle: e.g., CO2 and N2 fixation. These facts reveal an important, yet unobserved role for the Archaea in most plants and trees. With climate change already manifesting through warmer and drier summers in the northern hemisphere, the potential ameliorating effects of the gymnosperm microbiome may be very important for gymnosperm growth and survival under changing environmental conditions. Using a combination of molecular and culture-based techniques, I propose to (i) continue evaluating the role of external and internal plant tissue colonizing bacteria in gymnosperm growth and development; (ii) provide the first evidence of the occurrence and potential function of external and/or internal plant tissue colonizing Archaea in gymnosperm growth and development using molecular techniques; (iii) attempt to be the first to isolate and culture external and/or internal plant tissue colonizing Archaea from any plant; and (iv) evaluate the interactive effects of external and internal plant colonizing bacteria, fungi and Archaea (if available) on growth and development of gymnosperms under stressful environmental conditions that are anticipated to occur with a warming climate. These stressful conditions will include elevated temperatures, drought and nutrient deprivation, with studies performed under controlled environments. This work will be the first to evaluate the occurrence and role of the Archaea in gymnosperm growth and development. In addition, this work may result in obtaining the first Archaea strain(s) ever to be isolated from external and/or internal tissues of any plant species and to evaluate the interactive effects of bacteria, fungi and Archaea on gymnosperm growth under stressful conditions.