The laccase gene Gh Lac1 modulates fiber initiation and elongation by coordinating jasmonic acid and flavonoid metabolism

Cotton fibers are single cells originating in the epidermis of cotton ovules,and serve as the largest natural fiber source for the textile industry.In theory,all epidermal cells have the potential to develop into fibers,but only 15%–25%of epidermis cells develop into commercially viable lint fibers.We previously showed that Gh Lac1 participates in cotton defense against biotic stress.Here we report that Gh Lac1 also has a role in cotton fiber development.Gh Lac1 RNAi lines in cotton showed increased differentiation of fiber initials from epidermis and shortened fiber length,resulting in unchanged lint percentage.Suppression of Gh Lac1 expression led to constitutively hyperaccumulated jasmonic acid(JA)and flavonoids in ovules and fiber cells.In vitro ovule culture experiments confirmed the distinct roles of JA and flavonoids in fiber initiation and elongation,and showed that fiber development is spatially regulated by these chemicals:the increased fiber initiation in Gh Lac1 RNAi lines is caused by hyperaccumulated JA and rutin content during the fiber initiation stage and shortened fiber length is caused by constitutively increased JA and naringenin content during the fiber elongation stage.

Correlation, Regression and Path Analyses of Seed Yield Components in <i>Crambe abyssinica</i>, a Promising Industrial Oil Crop

In the present study correlation, regression and path analyses were carried out to decide correlations among the agro- nomic traits and their contributions to seed yield per plant in Crambe abyssinica. Partial correlation analysis indicated that plant height (X1) was significantly correlated with branching height and the number of first branches (P 2) was significantly correlated with pod number of primary inflorescence (P 3) was significantly correlated with number of secondary branches (P -grain weight (P 4) was significantly correlated with seed yield per plant (P 7) was significantly correlated with seed yield per plant (P -grain weight (P -grain weight (X8) was significantly correlated with seed yield per plant (P -grain weight contributed significantly to seed yield per plant at P 7) and 1000-grain weight (X8) to seed yield per plant (Y) is Y = 0.006 X7 + 1.222 X8 - 7.191. The path coefficient of pod number per plant to seed yield per plant was 0.967 and that of 1000-grain weight was 0.194. The determination coefficient of pod number per plant and 1000-grain weight to seed yield per plant was 0.983 and the determination coefficient of other agronomic traits was 0.130. Coefficient of variance indicated that the length of primary inflorescence showed the greatest variation, followed by seed yield per plant, pod number per plant, number of secondary branches, branching height, pod number of primary inflorescence, number of first branches, seed yield per plot, 1000-grain weight and plant height. It was suggested that seed yield per plant in Crambe might be improved by increasing the pod number per plant through selection or cultivation, but the negative correlation between pod number per plant and 1000-grain weight also needs to be considered.