Investigation of virus biodiversity in Antarctic terrestrial plants

Samples from Macquarie Island were collected between 1998 and 2004. Samples from Heard Island were collected during 2000. Continental samples were collected between 2004 and 2006. This project aims to confirm that viruses are the cause of disease symptoms observed in several plant species from Macquarie Island, and to characterise the viruses. These would be the first examples of terrestrial plant viruses found in Antarctica, and the southernmost plant viruses found. The results would be of fundamental biological significance, and will enable investigation of how plant viruses evolve in such an isolated location. The possibility of terrestrial plant viruses on Heard Island will also be investigated.A species from this project that has been entered into the Genbank database, a partial sequence of Stilbocarpa virus from Macquarie island - AF478691 (Genbank number).See also ASAC project 2152 (ASAC_2152).The fields in this dataset are:SpeciesDateLatitudeLongitudeCollection SiteGenbank NumberCollection NumberInternal Transcribed SpacersComments Project objectives: The project objectives, as stated in the project application round 2008/09, appear below:This project has already enabled identification and characterisation of a new virus in Stilbocarpa polaris on Macquarie Island. This is the first example of a terrestrial plant virus found in Antarctica, and is of of fundamental biological significance. It is the southernmost plant virus known, and occurs on one of the most isolated and geologically recent islands. We have determined the complete genomic sequence of this virus, and have started to analyse the dispersal and origins of this virus.The main objectives of the next phase of this project are:1. to further investigate the genetic variability, origins and evolution of the Stilbocarpa virus SMBV, and compare it with other badnaviruses to assess whether it has an extra gene compared with other viruses in the group2. to analyse its means of transmission between Stilbocarpa plants and its dispersal around the island, and the extent of its effect on the host plants (such as significantly reduced seed set).3. to analyse the effect of climate change, already happening on Macquarie Island, on SMBV and its host plants.4. to analyse disease symptoms observed in several other subantarctic plant species, especially Cardamine corymbosa, to test whether these species are also virus-infected. Totally different virus-like particles have also been observed by electron microscopy in one sample of diseased leaves of Stilbocarpa polaris from Macquarie Island. These will be further characterised.5. to investigate the biodiversity and dispersal of other plant pathogens such as fungi, and their consequences on plant health. A fungal pathogen of the moss Bryum argenteum from continental Antarctica has been identified, and two others will be characterised from mosses on Heard and Macquarie Islands.The further extension of this project will make use of specimens already collected on Heard and Macquarie Islands, to obtain as much information as possible about plant diseases in these remote locations, and their environmental adaptation to climate change.Taken from the 2008-2009 Progress Report:Progress against objectives:Good progress has been made with this project, in objectives where rabbit damage on Macquarie Island has not prevented progress.Analysis of DNA sequencing results for variants of the Stilbocarpa mosaic bacilliform virus has continued this year. Two papers are nearing completion on these results.It has proven difficult to analyse the means of transmission of the virus in Stilbocarpa at present, mainly due to rabbits completely eating plants at sites which were being monitored. However, this season we were able to sample some very young Stilbocarpa seedlings under plants difficult for rabbits to access, and this gives the possibility of testing for seed transmission of the virus.The potential new plant virus previously observed in Cardamine could not be followed up, as the area has been completely denuded of Cardamine plants by rabbits. An exclosure has been erected to attempt to germinate potentially infected seedlings in the area where diseased plants had been observed.Fungal infection of mosses colonising dead Poa foliosa tussocks was observed on Macquarie Island this year, and these colonies will be further examined.The results and publications are in line with the objectives of the project. Taken from the 2009-2010 Progress Report:Progress against objectives:Good progress has been made with this project, in objectives where rabbit damage on Macquarie Island has not prevented progress.Analysis of DNA sequencing results for variants of the Stilbocarpa mosaic bacilliform virus has continued this year. Two papers are nearing completion on these results.It has proven difficult to analyse the means of transmission of the virus in Stilbocarpa at present, mainly due to rabbits completely eating plants at sites which were being monitored.The potential new plant virus previously observed in Cardamine could not be followed up, as the area has been completely denuded of Cardamine plants by rabbits. An exclosure had been erected to attempt to germinate potentially infected seedlings in the area where diseased plants had been observed, but was removed this year as it had unfortunately been erected some 100m from the required site,and no infected Cardamine was growing inside the fencing. However, extensive searching in nearby locations this season has possibly revealed a new site for this potential virus, and samples will be analysed on their return to Australia in April.Fungal infection of mosses colonising dead Poa foliosa tussocks was again observed on Macquarie Island this year, and these colonies will be further examined.The results and publications are in line with the objectives of the project.

样本采集信息：麦夸里岛（Macquarie Island）的样本采集于1998至2004年间，赫德岛（Heard Island）的样本采集于2000年，大陆样本采集于2004至2006年间。本项目旨在确认麦夸里岛多种植物出现的病害症状由病毒引发，并对相关病毒进行鉴定与表征。本项目的研究成果将是南极地区发现的首例陆生植物病毒，也是迄今已知的最南端植物病毒，具有重要的基础生物学意义，同时可为探究植物病毒在极端孤立环境中的演化机制提供支撑。此外，本项目还将探究赫德岛是否存在陆生植物病毒。

本项目中已存入基因库（GenBank）的物种为来自麦夸里岛的Stilbocarpa病毒部分序列，其GenBank编号为AF478691。另可参考ASAC项目2152（ASAC_2152）。

本数据集包含以下字段：物种、采集日期、纬度、经度、采集地点、GenBank编号、采集编号、内部转录间隔区（Internal Transcribed Spacers）、备注。

项目目标（源自2008/2009年度项目申请书）如下：
本项目已成功在麦夸里岛的极地栗色草（Stilbocarpa polaris）中鉴定并表征了一种新型病毒，这是南极地区发现的首例陆生植物病毒，具有重要的基础生物学价值，同时也是已知最南端的植物病毒，其宿主所在的麦夸里岛属于全球最为孤立且地质年代最晚的岛屿之一。本团队已完成该病毒的全基因组测序，并启动了对其传播路径与起源的分析。
本项目下一阶段的核心目标包括：
1. 进一步探究Stilbocarpa花叶杆状病毒（SMBV）的遗传变异、起源与演化机制，并与杆状DNA病毒属（Badnavirus）的其他病毒进行比对，以评估该病毒是否相较于同组其他病毒多出一段额外基因；
2. 分析该病毒在极地栗色草植株间的传播途径与岛屿内扩散模式，以及其对宿主植物的影响程度（例如显著降低结实率）；
3. 分析麦夸里岛已发生的气候变化对SMBV及其宿主植物的影响；
4. 分析其他亚南极植物物种（尤其是圆叶碎米荠（Cardamine corymbosa））出现的病害症状，以验证这些物种是否也受到病毒侵染。此外，研究团队通过电子显微镜在麦夸里岛的一份患病极地栗色草叶片样本中观察到了形态迥异的类病毒颗粒，后续将对其进行进一步表征；
5. 探究其他植物病原物（如真菌）的生物多样性与传播模式，及其对植物健康的影响。目前研究团队已从南极大陆的银藓（Bryum argenteum）中鉴定出一种真菌病原物，并将对赫德岛与麦夸里岛苔藓中的另外两种真菌病原物进行表征。
本项目的后续拓展研究将利用已在赫德岛与麦夸里岛采集的标本，尽可能获取这些偏远地区植物病害及其对气候变化环境适应性的相关信息。

2008-2009年度进展报告：
本项目在未受麦夸里岛兔类啃食破坏干扰的研究目标上取得了良好进展。
本年度持续开展了Stilbocarpa花叶杆状病毒变异株的DNA测序结果分析，已有两篇相关论文即将完成。
目前分析该病毒在极地栗色草中的传播途径仍存在较大困难，主要原因是监测位点的植株已被兔类完全啃食。不过本季度研究团队成功在兔类难以抵达的植株下方采集到了部分幼小的极地栗色草幼苗，这为验证病毒是否可通过种子传播提供了可能。
此前在圆叶碎米荠中发现的潜在新型植物病毒未能继续开展研究，因为该区域的圆叶碎米荠已被兔类完全啃食殆尽。研究团队已搭建防兔围栏，尝试在曾发现患病植株的区域培育潜在感染的幼苗。
本年度在麦夸里岛的死亡多花早熟禾（Poa foliosa）草丛定植的苔藓中观察到了真菌感染现象，后续将对这些菌落展开进一步研究。
本项目的研究成果与发表计划均符合既定目标。

2009-2010年度进展报告：
本项目在未受麦夸里岛兔类啃食破坏干扰的研究目标上取得了良好进展。
本年度持续开展了Stilbocarpa花叶杆状病毒变异株的DNA测序结果分析，已有两篇相关论文即将完成。
目前分析该病毒在极地栗色草中的传播途径仍存在较大困难，主要原因是监测位点的植株已被兔类完全啃食。
此前在圆叶碎米荠中发现的潜在新型植物病毒未能继续开展研究，因为该区域的圆叶碎米荠已被兔类完全啃食殆尽。研究团队曾搭建防兔围栏，尝试在曾发现患病植株的区域培育潜在感染的幼苗，但由于围栏搭建位置偏离预定位点约100米，且围栏内未生长受感染的圆叶碎米荠，该围栏已于本年度拆除。不过本季度研究团队在周边区域进行了广泛搜寻，疑似发现了该潜在病毒的新采样位点，样本将于4月运回澳大利亚后开展分析。
本年度在麦夸里岛的死亡多花早熟禾草丛定植的苔藓中再次观察到了真菌感染现象，后续将对这些菌落展开进一步研究。
本项目的研究成果与发表计划均符合既定目标。