Comparative proteomic analysis of drought and high temperature response in roots of two potato cultivars

The experiment was carried out during two vegetation seasons from 25th of April to 10th of September. Two Polish potato cultivars, the drought-tolerant Gwiazda and drought-sensitive Oberon were used. Selected tubers with transverse diameters of 3 - 4 cm were pre-sprouted for 2 weeks before planting. Plants were grown in a vegetation hall in pots filled with a thin layer of gravel on the bottom and the universal vegetable soil substrate ‘Hollas’ (Agaris Polska Ltd., Poland) produced from peat with the addition of chalk at a pH range of 5.5-6.5. Additionally, in phase 20 of the BBCH-scale of plant development, MIS-3 (Intermag) fertilizer was applied. Water content (WC) in volumetric basis in soil pots was measured according Black (1965). Weather conditions during the years of study were monitored using a Weather Campbell Station (Campbell Scientific Inc.) located in close proximity, and a thermohygrograph placed between pots. Meteorological data of air temperature, the photosynthetically active radiation, and humidity were comparable in the years of study and favorable for potato development. Three weeks after the initiation of the tuberisation phase (56 DAP), plants were divided into 3 groups, each consisting of 6 plants. The first group of plants was subjected to soil drought (remained without irrigation, day/night temperature 22°C/18°C), the second one to high temperature (day/night temperature 38°C/25°C) and the third one was watered according to needs and at optimal temperature (control plants, day/night temperature 22°C/18°C). Stress application lasted 14 days and finished at 70 DAP. During this period, plants were placed in phytotron equipped with six Hortilux Schreder Lamps with Philips light bulbs of 1600 W each. Air humidity was in the range 65-70%. WC under 14 days of soil drought reached 30% (v/v), and remained 80% (v/v) in control and high temperature conditions. During the recovery period, after 14 days of stress treatment, WC reached control levels. Plant root material for proteomic research was collected on the 14th day of stress treatment (70 DAP).

本实验于两个生长季开展，时间为4月25日至9月10日。选用两个波兰马铃薯品种：耐旱品种‘Gwiazda’与干旱敏感品种‘Oberon’。遴选横径3~4 cm的种薯，于种植前开展2周的预萌芽处理。试验植株种植于生长室的盆钵内，盆钵底部铺有薄层碎石，栽培基质为以泥炭为原料、添加碳酸钙调至pH 5.5~6.5的通用蔬菜栽培基质‘Hollas’，由波兰Agaris Polska有限公司（Agaris Polska Ltd.）出品。此外，在植物生长发育BBCH分级（BBCH-scale）第20阶段，施加MIS-3（Intermag公司）肥料。盆钵土壤的体积含水量（Water Content，简称WC）参照Black（1965）的方法进行测定。
试验期间的气象条件通过邻近的坎贝尔气象站（Campbell Scientific Inc.）以及置于盆钵间的温湿记录仪进行监测。试验两年间的空气温度、光合有效辐射与空气湿度等气象数据均无显著差异，且均适宜马铃薯生长发育。块茎形成阶段启动3周后（种植后第56天，Days After Planting，简称DAP），将植株划分为3组，每组各6株。第一组植株施加土壤干旱胁迫（停止灌溉，昼/夜温度设置为22℃/18℃），第二组施加高温胁迫（昼/夜温度设置为38℃/25℃），第三组按需浇水并维持适宜温度（对照组植株，昼/夜温度设置为22℃/18℃）。
胁迫处理持续14天，至种植后第70天（DAP）结束。胁迫处理期间，植株被置于人工气候箱中，该气候箱配备6盏Hortilux Schreder植物生长灯，每盏灯搭载1600 W的飞利浦灯泡。空气湿度维持在65%~70%范围内。经过14天土壤干旱胁迫后，土壤体积含水量降至30%（体积分数），而对照组与高温胁迫组的土壤体积含水量维持在80%（体积分数）。胁迫处理结束后的恢复阶段，土壤体积含水量回升至对照组水平。用于蛋白质组学研究的植株根系样品，于胁迫处理第14天（种植后第70天，DAP）采集。