中国西南高黎贡山绿僵菌物种多样性及其垂直分布特征

云南高黎贡山具有多样化的生态系统和生物资源。为探清该地区绿僵菌属(Metarhizium)真菌的物种多样性及其不同海拔的垂直分布特征, 沿海拔梯度(600-3,800 m)在7种典型植被类型(I: 干热河谷; II: 季风常绿阔叶林; III: 暖性针叶林; IV: 中山暖性常绿阔叶林; V: 山地苔藓矮林; VI: 寒温性灌丛或草甸; VII: 流石滩稀疏植被)中调查绿僵菌资源。从生境土壤中分离菌株, 通过多基因(nrSSU、nrLSU、EF-1α、RPB1和RPB2)系统发育分析进行物种鉴定。结果表明, 高黎贡山绿僵菌物种资源丰富, 获得的161株菌株分属于12个物种(Metarhizium rileyi, M. viridulum, M. lepidiotae, M. brunneum, M. pingshaense, M. anisopliae, M. robertsii, M. guizhouense, M. indigoticum, M. pemphigi, M. campsosterni和Metacordyceps neogunnii), 其中M. indigoticum为中国新记录种, M. anisopliae complex中的物种(8种)较集中; 同时还采集到了绿僵菌的近缘属Nigelia属物种N. martiale。高黎贡山绿僵菌广泛分布于除类型VII (海拔3,600-3,800 m)外的6种植被类型(海拔600-3,400 m)中。中低海拔植被类型(I-IV)中菌株数量较多(≥23株)、物种多样性较高(4-9种), 而高海拔植被类型(V-VI)中菌株数量较少(2-8株)、物种较单一(1-2种)。中海拔的常绿阔叶林中绿僵菌资源最丰富, 其中季风常绿阔叶林(植被类型II)中的菌株数量(52株, 占总数的32.3%)和物种数(9种)最多; 中山湿性常绿阔叶林(植被类型IV)为其次(47株, 占总数的29.2%; 7种)。高黎贡山绿僵菌优势种现象明显, M. brunneum为最优势物种, 其菌株数占总数的46.6%, 在生境条件差异很大的6种植被类型(I-VI)中都存在, 说明该物种生态适应能力最强。

Species diversity and vertical distribution characteristics of Metarhizium in Gaoligong Mountains,southwestern China

Gaoligong Mountains in Yunnan Province, China have diverse ecological systems and biological resources. To understand the diversity and the vertical distribution of Metarhizium species at different elevations in this area, Metarhizium resources were investigated in seven typical vegetation types (i.e., I, dry-hot valley; II, monsoon evergreen broad-leaved forest; III, warm coniferous forest; IV, mod-montane humid evergreen broad-leaved forest; V, mountain moss dwarf forest; VI, cold shrubs of meadow; and VII, rocky beach sparsely vegetation) along an elevation gradient (600-3,800 m). Strains of Metarhizium were isolated from soils of the vegetations at different elevations and identified using multi-gene (nrSSU, nrLSU, EF-1α, RPB1, and RPB2) phylogenetic analysis. Our result indicated that the species of Metarhizium in Gaoligong Mountains were abundant and the obtained 161 strains represented 12 Metarhizium species, namely, M. rileyi, M. viridulum, M. lepidiotae, M. brunneum, M. pingshaense, M. anisopliae, M. robertsii, M. guizhouense, M. indigoticum, M. pemphigi, M. campsosterni, and Metacordyceps neogunnii, and most of them (8 species) belonged to M. anisopliae complex. Additionally, Nigelia martiale, a taxon close to Metarhizium was also found in this area. M. indigoticum is new to China. Fungi of Metarhizium in Gaoligong Mountains were widely distributed in six vegetation types at elevation between 600 m and 3,400 m, but not in type VII at the elevation of 3,600-3,800 m. The vegetations at the low and middle elevations (I-IV) harbored larger number of strains (≥ 23) and higher species diversity (4-9 species), whereas those at high elevations (V-VI) possessed fewer strains (2-8) and relatively limited species (1-2 species). Metarhizium resources were the most abundant in evergreen broad-leaved forests at the middle elevation. The monsoon evergreen broad-leaved forest (vegetation type II) possessed the largest number of Metarhizium strains (52 strains, 32.3% of the total) and species (9 species), while mid-montane humid evergreen broad-leaved forest (vegetation type IV) (47 strains, 29.2% of the total) was the next. The superior species phenomenon of Metarhizium was remarkable in Gaoligong Mountains, M. brunneum being the most dominant, at 46.6% of the total strain numbers. It widely exists in six vegetation types (I-VI) with very different habitat conditions, suggesting that this species has the highest ecologic adaptability.