Improved RAPD amplification of recalcitrant plant DNA by the use of activated charcoal during DNA extraction

An efficient procedure has been developed for DNA extraction from cotton by modifying the original CTAB method. The major improvement concerns the use of activated charcoal to bind resinous and coloured compounds which copurify with the DNA. The efficiency of amplification by RAPD was used as a criterion to evaluate the action of activated charcoal. Twenty-five random decamers from Operon Technologies were used to compare DNA samples extracted in the presence or absence of activated charcoal. The results in terms of amplification suggest that the use of activated charcoal in DNA extraction enhances RAPD amplification. This technique was initially developed for cotton but it has been applied successfully to other recalcitrant plants such as coffee, rubber tree, cassava and banana.     

Complementary conservation strategies for the genus Coffea: A case study of Mascarene Coffea species

No single conservation technique can adequately conserve the full range of genetic diversity of a target species or genepool. To optimize the efficiency of germplasm conservation, a range of conservation techniques needs to be applied simultaneously. In this paper we review the progress made in the application of both in situ and ex situ complementary conservation strategies and techniques to the conservation of the genus Coffea and identify areas where more research work is required. Traditionally, Coffea species have been conserved ex situ as living plants in field genebanks due to their intermediate seed storage behaviour. However, progress made in the field of biotechnology in recent years have made it possible to envisage the use of in vitro, slow growth and cryopreservation for medium- and long-term conservation of Coffea germplasm, respectively. In situ conservation is also an important option for long-term conservation, but there are no genetic reserves specifically set up for conserving Coffea. Protected areas and managed reserves offer the best opportunities for conserving Coffea. A case study for Mascarene Coffea in Mauritius is presented and a strategy for their conservation is discussed.     

Gas exchanges and chlorophyll fluorescence of young coffee plants submitted to water and nitrogen stresses

Abstract

This research aims to evaluate the impact of nitrogen deprivation and water stress on gas exchange and chlorophyll fluorescence in young plants of five cultivars of Arabic coffee. A factorial experiment 5 (cultivars) × 3 (treatments: control without stress, water stress of ?1.5?MPa and stress of N – 0.0?mmol L^?1 N) was carried out in a complete randomized block design with three replicates. Before being submitted to the treatments, the plants were grown in a greenhouse for 240?days, and then transferred to a growth chamber under controlled conditions. Subsequently, after the experimental period of 96?h we measured photosynthetic rate (A), stomatal conductance to water vapor (g_s), transpiratory rate (E), internal and external carbon ratio (Ci/Ca), water use efficiency (A/E), electron transport rate (ETR), actual quantum yield of PS II electron transport (φFSII), and maximum photochemical efficiency of PS II (Fv/Fm). Water stress reduced A, g_s, E, A/E, ETR, φFSII, and Fv/Fm. The nitrogen deficiency reduced ETR, φFSII, and Fv/Fm. Under short-term water stress Catuaí Vermelho maintain the A values due to better stomatal control, reduced water lost by transpiration (E) and better water use efficiency A/E, while Mundo Novo and Acauã show lower damage to Fv/Fm. Short-term nitrogen stress has low impact on A of young plants of Coffea arabica cultivars with adequate N-nutrition.     

广东咖啡炭疽病病原菌初步鉴定及防治药剂筛选

[目的]明确引起广东咖啡炭疽病的病原菌种类并筛选防治药剂.[方法]采用组织分离法对采集到的疑似炭疽病咖啡叶片进行分离,单孢纯化后利用柯赫氏法则验证其致病性,结合菌株的形态学特征和多基因序列(ITS、TUB2、GAPDH、CHS、ACT和GS)的系统发育分析对病原菌进行鉴定;利用菌丝生长速率法测定4种常用杀菌剂对病原菌的...