Virus symptom expressions on Musa landraces in 1999, 2000 and 2004 in southern Nigeria: Cucumber mosaic virus (CMV) disease incidence and subgroup differentiation

Musa landraces (469) from 73 villages in 10 states in 1999, 2000 and 2004 in southern Nigeria were visually assessed to determine virus symptoms associated with CMV disease. CMV indexing was done using dot-blot immunoassay and ELISA. Monoclonal antibodies were used to group CMV isolates in 2004. Symptoms of interveinal chlorosis and chlorotic streaks were observed in 22.4 and 17.9% of the Musa samples with CMV disease incidences of 17.1% and 14.7%, respectively. Other virus symptoms accounted for between 1.5 and 12.2% of the total leaf samples while 13.9% were asymptomatic. CMV incidence in asymptomatic leaf samples was as high as 10.4% while the virus incidence in the other symptom types were between 0.9 and 7.9%. The incidences of CMV in both the symptomatic and asymptomatic plants in 1999, 2000 and 2004 were between 1.3 and 18.7%, 1.9 and 26.9% and 4.9 and 26.4%, respectively.     

How endogenous plant pararetroviruses shed light on Musa evolution

Background and Aims Banana genomes harbour numerous copies of viral sequences derived from banana streak viruses (BSVs) – dsDNA viruses belonging to the family Caulimoviridae. These viral integrants (eBSVs) are mostly defective, probably as a result of ‘pseudogenization’ driven by host genome evolution. However, some can give rise to infection by releasing a functional viral genome following abiotic stresses. These distinct infective eBSVs correspond to the three main widespread BSV species (BSOLV, BSGFV and BSIMV), fully described within the Musa balbisiana B genomes of the seedy diploid ‘Pisang Klutuk Wulung’ (PKW).Methods We characterize eBSV distribution among a Musa sampling including seedy BB diploids and interspecific hybrids with Musa acuminata exhibiting different levels of ploidy for the B genome (ABB, AAB, AB). We used representative samples of the two areas of sympatry between M. acuminata and M. balbisiana species representing the native area of the most widely cultivated AAB cultivars (in India and in East Asia, ranging from the Philippines to New Guinea). Seventy-seven accessions were characterized using eBSV-related PCR markers and Southern hybridization approaches. We coded both sets of results to create a common dissimilarity matrix with which to interpret eBSV distribution.Key Results We propose a Musa phylogeny driven by the M. balbisiana genome based on a dendrogram resulting from a joint neighbour-joining analysis of the three BSV species, showing for the first time lineages between BB and ABB/AAB hybrids. eBSVs appear to be relevant phylogenetic markers that can illustrate the M. balbisiana phylogeography story.Conclusion The theoretical implications of this study for further elucidation of the historical and geographical process of Musa domestication are numerous. Discovery of banana plants with B genome non-infective for eBSV opens the way to the introduction of new genitors in programmes of genetic banana improvement.     

芭蕉科花蜜腺形态比较：兼论其与传粉者的关系（英文）

对狭义芭蕉科3个属的代表性种芭蕉(Musa basjoo)、象腿蕉(Ensete glaucum)和地涌金莲(Musella lasiocarpa)的花蜜腺形态进行了比较研究。结果表明它们的蜜腺属于隔膜蜜腺。雌花的蜜腺着生于子房的上部,胚珠的上方;雄花蜜腺占据了整个败育子房的位置。蜜腺结构由许多腔道组成,这些腔道在横切面上呈现出复杂的发散式迷宫状结构。这3种植物花蜜腺的栅栏状表皮细胞、维管束和蜜腺开口方式相似,而从纵切面和横切面上观察其结构存在一些差异。PAS反应显示象腿蕉泌蜜组织中淀粉粒含量高于其他两个种;芭蕉和象腿蕉的蜜腺腔里有许多纤维状物质存在。3种植物的传粉综合征多样化,花序和花的特征(如花序下垂或直立、苞片的颜色、泌蜜量和泌蜜时间等)和传粉样式之间有密切关系。它们的蜜腺结构和传粉者行为之间没有明显的相关性,但是胶质或水质的花蜜对传粉者的取食方式有一定影响。     

Efficacy of RAPD,ISSR and DAMD markers in assessment of genetic variability and population structure of wild Musa acuminata colla

Physiology and Molecular Biology of Plants - North east India is considered as one of the major biodiversity hotspots worldwide and centre of origin of several plant species including Musa. Musa...     

Chilling-Induced Ethylene Production in the Peel and Pulp of Banana

Ethylene production rates and 1-aminocyclopropane-1-carboxylic acid (ACC) synthetase activities were 0. 78,0.91 nl· g-l ·h-land 0.02,0.05 nmol·g-1·h-1 respectively in the peel and pulp of newly harvested banana fruits(Musa acuminata Colla “warf cavendish”),their ethylene-forming enzyme(EFE)activities were yet as high as 10.5 and 5.1 nl·g-1·h-1. When the fruits were chilled at 1.5℃ ,the ethylene production and EFE activities of the peel and pulp kept decreasing with the time course of chilling treatment. However, after these chilled fruits were transferred to 20℃ for 24 h,their ACC synthetase activities increased markedly,and ethylene production had separate peaks(1.75 and 2.45 nl·g-1 ·h-1) in the peel and pulp. In this case,the endogenous low content of S-adenosylmethionine (SAM)in vivo was insufficient for its ACC synthesis, The inhibitory effect of cycloheximide on ACC synthesis showed that chilling-induced ethylene production was mainly the result of activity of the resynthesized ACC synthetase induced by chilling treatment. The production of chilling-induced ethylene could be good indicator of chilling injury, but it is unlikely an indicator of chilling damage during ripening process in banana. In the severly chilling-injured fruits, both the peel and pulp still had the capability of converting ACC to ethylene.     

Genetic transformation of Cavendish banana (Musa spp. AAA group) cv 'Grand Nain' via microprojectile bombardment

 An effective method has been developed for the stable transformation and regeneration of Cavendish banana (Musa spp. AAA group) cv 'Grand Nain' by microprojectile bombardment. Embryogenic cell suspensions were initiated using immature male flowers as the explant. Cells were co-bombarded with the neomycin phosphotransferase (nptII) selectable marker gene under the control of a banana bunchy top virus (BBTV) promoter or the CaMV 35S promoter, and either the β-glucuronidase (uidA) reporter gene or BBTV genes under the control of the maize polyubiquitin promoter. Plants were regenerated, under selection with kanamycin, that were co-transformed with nptII and either the uidA or BBTV genes. Molecular characterisation of transformants demonstrated that the transgenes had been stably integrated into the banana genome. Received: 22 June 1998 / Revision received: 29 March 1999 / Accepted 1 May 1999     

Pollination Ecology of a Pioneer Species: Musa itinerans (Musaceae) in Xishuangbanna,South Yunnan,China

Pollination ecology of Musa itinerans Cheesman (Musaceae), a pioneer species in the tropical rain forest, was explored in Xishuangbanna, South Yunnan, China. This research involved flowering phenology, nectar production, visitation patterns of pollinators and bagging experiments. It was found that (1) flowering of M. itinerans occurred a whole year round with a peak at the early dry season (Nov.) and the daily flowering pattern had two obvious peaks in the early morning and in the late evening, respectively; (2) nectar production occurred at two obvious peaks, during the day and in the night-time (from 8 am to 12 pm, and from 8 pm to 12 am, respectively), which allowed the two different foragers to visit at specific times; and (3) long-tongue fruit bats ( Macroglossus sobrinus ) and sunbirds ( Arachnothera longirostris ) were both effective pollinators of Musa itinerans.     

Relationship between Ripening and the Development of Banana Anthracnose Caused by Colletotrichum musae (Berck. and Curt.) Arx

Wound anthracnose caused by Colletotrichum musae is the main disease affecting the quality of export bananas from the French Antilles. Little is known about the effects of ethylene on the development of wound anthracnose and quiescent anthracnose. The results of our experiments with 1‐methylcyclopropene (1‐MCP), an ethylene receptor site inhibitor, clearly revealed that ethylene was not directly involved in triggering rot development. Quiescent anthracnose symptoms were found to appear only after bananas began ripening. In contrast, wound anthracnose developed just as quickly in ‘green 1‐MCP‐treated bananas’ as in ‘yellow ripening bananas’. In cases of wound anthracnose, contrary to quiescent anthracnose, rot development was not dependent on the extent of peel ripeness.     

广东大蕉分类位置的探讨

本文从形态特征,减数分裂,染色体配对以及核型分析等三个方面探讨了广东大蕉在属内的分类位置问题,根据１５个形态特征的比较评分,染色体组同源性和核型特征的分析结果,广东大蕉应属ＢＢＢ类型。它的学名应为Ｍｕｓａ ｂａｌｂｓｉａｎａ Ｃｏｌｌａ（ＢＢＢｇｒｏｕｐ）。     

Nematicidal Effects of Oxamyl Applied to Leaves of Banana Seedlings

Foliar applications of oxamyl prevented nematodes from invading roots of diploid bananas. One spray with 1,250 μg/ml was more effective than 1, 2, or 3 sprays with 625 μg/ml applied at 5-day intervals. After 3 sprays with 1,250 μg/ml, invasion may be prevented for up to 4 weeks and possibly longer. Washing roots after oxamyl treatments prevented nematicidal control. When applied to nematode-infected plants, three sprays of oxamyl decreased nematode populations in the roots.