Seasonal,tissue and age influences on frequency and biodiversity of endophytic fungi of Citrus sinensis in Iran

A total of 4,009 endophytic fungal isolates were recovered from healthy leaves, bark and xylem of Citrus sinensis in different seasons and age‐classes. Corresponding to those factors, the majorities of fungal isolates were recovered from leaves, 2‐yr‐old trees and winter, respectively. Fungal isolates were initially categorized based on cultural and morphological characters, and representatives of each morphotype were subjected to molecular identifications based on ITS‐rDNA and β‐tubulin sequences. All isolates obtained in this study belonged to the phyla Ascomycota and Basidiomycota assigned to 30 fungal taxa. The most abundant fungal species were Alternaria spp. Species diversity indices of Margalef richness and Shannon–Wiener revealed a high diversity of fungal taxa recovered from leaf and during winter. Frequency (%) of fungal endophytes was highest in winter followed by summer, autumn, and spring significantly, whereas the corresponding sequence was winter, autumn, summer and spring for the diversity of endophytic fungi. Overall, the results of this study based on the community and diversity of endophytic fungal species in C. sinensis showed that the type of plant tissue, season of sampling and age of tree play a driving role on their abundance while their diversity was mainly dependent on the type of plant tissue, season of sampling than on the age of tree.     

Identification and characterization of fungi associated with internal wood lesions and decline disease of willow and poplar trees in Iran

During the study of fungal trunk pathogens associated with urban trees decline in Shiraz (Iran), a serious decline of willow and poplar trees was observed. Therefore, an investigation was conducted on these trees in some areas of this city during spring and summer 2012 and 2013, to determine the main fungal trunk pathogens associated with these ornamental plants. Plant materials were collected from trees exhibiting disease symptoms such as yellowing, shoot canker, shoot dieback, defoliation and internal wood necrosis and decayed wood. Fungal isolations were made from discoloured or decayed wood tissue onto 2% malt extract agar (MEA) amended with streptomycin sulphate. Nine species, Fomes fomentarius, Diplodia seriata, Lasiodiplodia theobromae, Dothiorella sarmentorum, Neoscytalidium hyalinum, Diatrype whitmanensis, Phaeoacremonium rubrigenum, P. aleophilum and P. parasiticum, were identified based on morphology and DNA sequence comparisons. Pathogenicity tests were performed on detached shoots of willow and poplar trees under greenhouse conditions. Lasiodiplodia theobromae caused the longest lesions on willow. On poplar shoots, the longest lesions were caused by P. parasiticum. Diplodia seriata produced the smallest lesions on both woody hosts. First reports from willow wood include P. parasiticum, P. rubrigenum, D. whitmanensis, L. theobromae, D. seriata and N. hyalinum, while new reports from poplar wood include P. parasiticum and Do. sarmentorum. Based on our knowledge, this is also the first report of D. whitmanensis in Iran.     

Decline‐associated Phaeoacremonium species occurring on forest trees in the north of Iran

Between 2013 and 2015, several surveys were conducted throughout forest areas in the north of Iran with the aim of isolating and identifying fungi present on trees showing decline symptoms. Fungal species, isolated from symptomatic wood tissues of various tree genera, including Zelkova, Acer, Parrotia, Quercus, Diospyros, Fagus, Fraxinus, Populus, Pinus, Pterocarya, Gleditsia, Carpinus, Ulmus, Crataegus, Alnus, Mespilus, Punica, Cydonia, Cupressus and Prunus, were morphologically identified and characterized. A molecular identification based on comparisons of DNA sequences of the β‐tubulin gene allowed us to identify seven species belonging to Phaeoacremonium; namely, Phaeoacremonium parasiticum, Pm. alvesii, Pm. minimum, Pm. iranianum, Pm. scolyti, Pm. fraxinopennsylvanicum and Pm. croatiense were isolated and identified. Phaeoacremonium minimum was the most common species and isolated from Gleditsia caspica, Parrotia persica, Cydonia oblonga and Alnus glutinosa. Pathogenicity on selected plants using a mycelium plug inoculation method revealed that most of these species are pathogenic to all the tested trees, with Pm. parasiticum and Pm. minimum being the most pathogenic species. According to host plant species and geographical distribution, the majority of Phaeoacremonium species found represent new records. This is also the first report of Pm. croatiense in Iran and outside Croatia.     

Dieback and decline of wild almond (Amygdalus scoparia Spach) in the Harat protected forest of Yazd Province,Iran

Wild almond (Amygdalus scoparia) is a dominant shrub species in mountain forests of the Irano‐Turanian region. Dieback and decline symptoms of wild almond shrubs were first observed in Harat protected forest (Yazd, Iran) in the autumn of 2014. Since then, the incidence and severity of the disease have increased. To study the aetiology and estimate losses from the disease, field studies were conducted in 2016 and 2017. For this purpose, eight stands were selected, in which 24%–99% of the trees were wild almond in their species composition. In total, 50 cankers and 50 infected twigs of wild almond shrubs were collected. Fungal isolates were identified based on morphological and cultural characteristics, as well as sequence data of ITS1 + 5.8S + ITS2 rDNA. Pathogenicity of fungi was checked on detached shoots and evaluated after 40 days by measuring the discoloured lesion length at the inoculation site. Among 681 wild almond shrubs checked, 84.44% showed decline symptoms with different severities; only 15.56% did not show observable disease symptoms. The most frequent colonizers of infected tissues taken from cankers were Wilsonomyces carpophilus (56%), Thyrostroma cornicola (40%) and Collophorina paarla (30%). Infected twigs were extensively colonized by W. carpophilus (36%), Th. cornicola (24%) and Ulocladium consortiale (24%). Other species, such as Endoconidioma populi, Microsphaeropsis olivacea, Trichoderma asperellum, Paecilomyces formosus, Saccothecium rubi, Preussia sp. and Chaetomium globosum, had lower isolation frequencies. W. carpophilus, Th. cornicola, C. paarla and U. consortiale were found as pathogens on detached wild almond shoots. Based on the frequency of the isolates and the pathogenicity tests, four fungi, such as W. carpophilus, Th. cornicola, C. paarla and U. consortiale, are considered serious contributing agents playing a significant role in the dieback and decline of wild almond. All isolated species are reported for the first time on the wild almond shrubs of the world.     

High genetic diversity at the inter-/intra-host level of Cherry leaf roll virus population associated with the birch leaf-roll disease in Fennoscandia

A viral epidemic associated with the Cherry leaf roll virus (CLRV) has emerged in Betula species in Fennoscandia, exhibiting quick and effective spread during the last 15 years. A population genetics approach is chosen in order to characterise the virus diversity and the sources of genetic variation aiming to investigate the epidemiology of the pathogen. In a CLRV population from Rovaniemi urban parks and a population that occurred after infecting young Betula seedlings with scions from the original Finnish trees, the genetic diversity is found to be remarkably high, mixed infections by CLRV variants from different phylogenetic groups are detected in single trees, while recombination is evidenced to occur. The estimated genetic variability is high and the CLRV haplotypes detected exhibit clear clustering and belong to different phylogenetic groups. The structure of the viral population reveals a pathogen with high evolutionary potential assumed to carry on its effective spread.     

苏北杨树新造林地溃疡病病原菌的鉴定

2001年以来,苏北地区每年春季杨树新造林发生大面积死亡,在死亡或濒临死亡的杨树枝干上,几乎都有溃疡病症状的病斑发生。本试验通过对杨树新造林地(I-72杨)溃疡病病组织的分离、纯化培养获得10余株菌株,经接种、发病后再分离,获得6株拟茎点霉菌株;进一步克隆并分析供试菌株核糖体DNA-ITS区域的序列,结果是分离菌株与GenBank中Phomopsis eucommiicola的ITS序列有同源性,相似性达到99%。因此将该拟茎点霉菌确定为Phomopsis eucommiicolaC.Q.Chang,Z.D.JiangP.K.Chi,。该病原菌侵染杨树引起杨树新造林木溃疡病是首次报道。     

河南省臭椿炭疽病病原鉴定

目的 鉴定引起河南省洛阳市嵩县天池山国家森林公园臭椿炭疽病病原菌,为该病害的防控提供依据。 方法 采用常规组织分离法进行病原分离,利用形态学和多基因系统发育分析相结合的方法对分离菌株鉴定并进行致病性测定。 结果 从病组织中共分离获得11株菌株,所有菌株在PDA培养基上菌落特征表现一致,正面菌落先白色后灰色,背面黑色,分生孢子为圆柱状,两端钝圆,单孢,无色,初步鉴定分离菌株为炭疽菌Colletotrichum spp.。选取代表菌株CH-1和CH-3接种臭椿叶片,有伤条件下接种均能引起臭椿叶片发病,发病叶片症状与田间一致,柯赫氏法则验证成立;经多位点基因（ITS、ACT、TUB2、CHS-1和GAPDH）系统发育分析,发现分离菌株与果生炭疽菌C. fructicola聚集在同一个分支上,支持率达到99%。 结论 本研究首次采用形态学结合多基因系统发育研究,明确发生在河南省洛阳市嵩县天池山国家森林公园的臭椿炭疽病为果生炭疽菌C. fructicola所致。     

青海西北部沙棘立木腐朽病初报

笔者在我国青海西北部采集沙棘Hippophae rhamnoides心材腐朽病的病原菌子实体,经对样品的分子序列进行系统发育分析,确认该地区沙棘腐朽病的病原菌为鼠李嗜蓝孢孔菌Fomitiporia rhamnoides。该菌过去作为分类学种类仅在我国河北有报道,且未说明该菌是否为病原菌。本文中首次报道鼠李嗜蓝孢孔菌在我国青海西北部造成心材白色腐朽,该病主要发生在沙棘成熟林分内,病原菌通过沙棘伤口侵染,最后风折导致沙棘死亡。     

The role of agroforestry in industrialized nations: the southern hemisphere perspective with special emphasis on Australia and New Zealand

Agroforestry in Australia and New Zealand is dominated by silvopastoralism. Farmers may employ combinations of shelterbelts, shade trees, widely spaced trees over pasture, or more densely planted woodlots. In addition to wood production and shelter, erosion control, amenity and landscape planting, and conservation of natural forest are often important. Many farm forestry people show considerable innovation.In temperate wetter areas of Australia, eucalyptus and, to a lesser extent,Pinus radiata (radiata pine) dominate agroforestry tree plantings for wood, shade, shelter, and salinisation and erosion prevention. The One Billion Tree Program, initiated by the Australian Federal Government, provides limited funding for tree planting. Joint farmer ventures with the State or local industry are also common. Most State governments also provide advice, and planting is tax deductible. Local landcare groups, formed to encourage sustainable agriculture, often promote tree planting, particularly where soil degradation is a problem. Melbourne University and other Techncial Institutes offer training in agroforestry.In New Zealand, a third of the farms require trees for soil conservation. This, together with the growing recognition of the financial benefits of planting trees, has resulted in small landowners doing most of the current planting of 80,000 to 100,000 ha yr^–1. Most farmers plant radiata pine, but eucalyptus and other hardwoods, including willows and poplars, are also widely used. There are almost no government incentives for tree planting in New Zealand. The Farm Forestry Association is the major extension organization. Lincoln University has an important teaching and research commitment, and the New Zealand Forest Research Institute Limited has developed very useful management models.     

江西省上阔下竹复合系统类型调查与分析

基于江西省毛竹林经营现状,调查分析了竹阔混交林分中山顶阔叶林与山体中下部毛竹纯林所构成的复合系统（简称上阔下竹）特征及其对毛竹林生长指标的影响。结果显示：江西上阔下竹系统可分为4种类型,分别为高阔中海拔陡坡多石型、中阔低海拔缓坡中石型、低阔低海拔缓坡少石型、低阔中海拔斜坡中石型,其中以中阔低海拔缓坡中石型生物多样性最为丰富、竹林生物量也最高。各类型系统中上位阔叶林树种多样、层次分明、生物多样性丰富,有利于提高林分的生态安全。同时,上位阔叶林能有效保持林地水分和养分并供给下位毛竹林,促进毛竹生长,提高毛竹林的胸径和生物量。     

Effect of post-planting inoculation with Bradyrhizobium sp and mycorrhizal fungi on the growth of Brazilian rosewood,Dalbergia nigra Allem. ex Benth., in two tropical soils

Six months after planting, seedlings of the leguminous treeDalbergia nigra, known as Brazilian rosewood, wereinoculated with a selected Bradyrhizobium strainBHICB-DN 15,either alone or in combination with mycorrhizal fungi to determine their effecton the growth of D. nigra in Atlantic forest andeucalyptussoils. Height growth of D. nigra was similar in both soilsand six months after inoculation Bradyrhizobium did notaffect the D. nigra height growth, but it did improve drymass and especially in the nitrogen content of plants grown in eucalyptus soil.The success of the delayed inoculation with BHICB-DN 15 confirms its competitiveability vis-à-vis indigenous soil rhizobia. Co-inoculationof BHICB-DN 15 and mycorrhizal fungi did not increase plant dry weight,nitrogenand phosphorus content or mycorrhizal colonization. These results suggest thatthe BHICB-DN 15 strain had no synergistic relationship with the mycorrhizalfungi or that there was incompatibility between symbionts, in both soils.