Purpose

Fructans are easily mobile storage carbohydrate in crops. In barley (Hordeum vulgare L.), a variable amount of fructans is stored in the stem or remobilized to the grain after flowering, which might be impacted by the photosynthetic performance. The aim of this work was to analyze the connection between photosynthetic performance, fructan content and activity of genes involved in the synthesis (1-SST, sucrose:sucrose-1-fructosyltransferase and 6-SFT, sucrose:fructan-6-fructosyltransferase) and remobilization (1-FEH, fructan 1-exohydrolase) of fructans at three developmental growth stages: flowering, grain filling and ripening stage in two spring barley cultivars differing in their yield.

Methods

Photosynthetic performance was assessed by using chlorophyll a fluorescence measurement expressed as total performance index (PI_total) and maximum quantum yield (Fv/Fm), fructan content was determined spectrophotometrically using resorcinol reagent and gene activity by semi-quantitative RT-PCR.

Results

The PI_total was higher in cultivar Jaran than in Astor, indicating its better photosynthetic performance. Cultivar Jaran accumulated significantly less fructans in three basal internodes compared to cultivar Astor. Such observations could be explained by concurrent synthesis and remobilization and better sink strength in cultivar Jaran due to congruent expression of genes regulating biosynthesis and fructan remobilization. On the other hand, the higher fructan content in basal internodes of cultivar Astor could possibly be the consequence of lower expression of 1-FEH gene responsible for fructan remobilization.

Conclusion

Our results showed that fructan synthesis and remobilization to the grain are dependent on synchronized activity of regulatory genes, indicating a strong influence of photosynthetic performance and genotype.

中文翻译：

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大麦品种中果聚糖的不同积累和迁移与光合性能和产量形成对比

目的

果聚糖是易于在农作物中移动存储的碳水化合物。在大麦（大麦属大麦）中，可变数量的果聚糖在开花后被储存在茎中或转移到谷粒上，这可能受到光合作用的影响。这项工作的目的是分析光合作用的性能，果糖含量和参与合成的基因（1-SST，蔗糖：蔗糖-1-果糖基转移酶和6-SFT，蔗糖：果聚糖-6-果糖基转移酶）之间的联系。在两个产量不同的春季大麦品种的三个发育生长阶段：果聚糖的固定化（1-FEH，果聚糖1-外切水解酶）：开花，籽粒充实和成熟阶段。

方法

使用叶绿素评估光合性能，荧光测量表示为总性能指数（PI _total）和最大量子产率（Fv / Fm），果糖含量通过间苯二酚试剂分光光度法测定，基因活性通过半定量RT-PCR进行测定。

结果

Jaran品种的PI_总含量高于Astor品种，表明其光合性能更好。与品种阿斯特（Astor）相比，Jaran品种在三个基节间积累的果聚糖少得多。可以通过同时进行合成和迁移以及在Jaran品种中更好的吸收强度来解释这些观察结果，这归因于调节生物合成和果聚糖迁移的基因的一致表达。另一方面，品种Astor的基节间的果聚糖含量较高，可能是负责果聚糖固定的1-FEH基因表达降低的结果。

结论

我们的结果表明，果聚糖的合成和向谷物的迁移取决于调节基因的同步活性，这表明光合性能和基因型的影响很大。