The G-protein subunits FGA2 and FGB1 play distinct roles in development and pathogenicity in the banana fungal pathogen Fusarium oxysporum f. sp. cubense

The soil-borne fungus Fusarium oxysporum f. sp. cubense causes banana (Musa spp.) vascular wilt. Here, we examine the roles of G-protein α and β subunit genes fga2 and fgb1 in F. oxysporum development and pathogenicity. Deletion of either or both genes led to increased heat resistance, lower cAMP levels, and enhanced pigmentation, whereas phenotypic defects of colony morphology and reduced conidiation were seen in Δfgb1 and Δfga2/Δfgb1 deletion strains but not in Δfga2. Conversely, Δfgb1 retained greater virulence against banana, suggesting that FGA2 regulates fungal virulence whereas FGB1 modulates both development and virulence, potentially via the cAMP-dependent protein kinase A pathway.     

Functional analysis of the G-protein α subunits FGA1 and FGA3 in the banana pathogen Fusarium oxysporum f. sp. cubense

The asexual fungus Fusarium oxysporum f. sp. cubense (Foc) is the causal agent of fusarium wilt in bananas (Musa spp.). This fungus poses a threat to banana production throughout the world. Here, two Foc genes, fga1 and fga3, were functionally characterized. These genes encode proteins homologous to the G-protein α subunits GPA1 from Saccharomyces cerevisiae and MAGC from Magnaporthe grisea, respectively. The deletion of fga1 leads to a phenotypic defect in colony morphology and reductions in vegetative growth, conidiation and pathogenicity against the banana plant (Musa spp. cv. Brazil), which was not observed for the Δfga3 deletion mutant. Intriguingly, both Δfga1 and Δfga3 deletion mutants showed declines in intracellular cyclic AMP levels and increases in heat resistance, suggesting that FGA1 regulates growth, development, pathogenicity, and heat resistance, whereas FGA3 modulates heat resistance, potentially through the cAMP-dependent protein kinase A pathway. These findings offer insights into the roles of the G-protein α subunits in the development and pathogenicity of the fungus Foc.     

基于DCL的表格数据处理

利用AutoCad软件包提供的PDB（可编程对话框）工具，结合AutoLisp的对话框控制语言DCL，将原来把数据表格固化在程序内部的方式，改为用外部数据文件形式来保存数据表格，再通过AutoLisp将外部数据文件与DCL连接，实现用户可视化参数选择界面。     

Leaf carbon isotope discrimination,ash content and K relationships with seedcotton yield and lint quality in lines of Gossypium hirsutum L.

In a two-year (2005–2006) study conducted at three sites in central (Larissa) and northern (Alexandroupolis, Thessaloniki) Greece, we aimed to investigate the relationships between seedcotton yield and lint quality with leaf physiological traits (carbon isotope discrimination-Δ, ash content and K concentration). Eighteen lines with their original cultivars (Christina, Flora, Corona) were tested under the ultra-low density of 1.2 plants m⁻². In combined data over years, a significant, positive correlation between seedcotton yield and Δ or ash content was found only in the driest and lowest-yielding site (Larissa), indicating that genotypes that keep their stomata open and in turn exhibit the highest Δ values, had an advantage in such environments. In pooled data from the two most productive sites (Thessaloniki and Alexandroupolis), which had the highest Δ and ash content values, evidenced a negative correlation between seedcotton yield and both physiological traits. Seedcotton yield was negatively related with leaf K concentration in Larissa and Alexandroupolis but no significant relationship was found in Thessaloniki where leaf K concentration was below adequacy limit. Δ was positively related with ash content which suggests that the latter could be a putative surrogate of Δ. Negative correlation between Δ and leaf K concentration was found in two out of three sites (Larissa and Thessaloniki) as well as between ash content and K in one site (Larissa). These findings suggest that K accumulation in leaves is not just a passive procedure via transpiration stream. Significant, linear relationships of each physiological trait between sites showed that genotypic ranking was constant in the three sites, an indication of heritability. Ash content had the highest significance levels and correlation coefficients. Even though significant genotypic differentiation was observed for the three physiological and two of the lint quality traits (i.e. fibre length, micronaire) determined in Alexandroupolis, only a weak, negative relationship between fibre length and leaf K concentration was evident. In sum, leaf physiological traits (Δ, ash content and K concentration) could not be reliably used for yield selection in cotton owing to site-specific effects, which prejudice the yield–physiological traits relationship. Ash content–Δ relationship merits further research in order the former to be established as a putative surrogate of Δ.