iTRAQ-based quantitative proteome analysis reveals metabolic changes between a cleistogamous wheat mutant and its wild-type wheat counterpart

Accumulation of mutations in the AP2 homoeologs causes suppression of anther extrusion with altered spike and culm development in hexaploid wheat

Cleistogamy or closed flowering is a widely used trait in barley (Hordeum vulgare) breeding because it reduces the risk of fungal infection in florets at anthesis. Cleistogamy in barley is caused by a point mutation within the microRNA172 (miR172) target site of the Cly1 gene, which encodes the Apetala2 (AP2) transcription factor. Because cleistogamy is not apparent in cultivars of hexaploid wheat (Triticum aestivum), a strategy to develop cleistogamous wheat was proposed by inducing point mutations in all three AP2 homoeologs, which are the wheat orthologs of barley Cly1. In this study, we investigated the effects of miR172 target site mutations on wheat cleistogamy using double mutants by combining three previously obtained mutant alleles (AP2-A1, D1 and D2) in a near-isogenic background. The AP2-D2 allele had the greatest effect on reducing the anther extrusion rate and lodicule size compared with the other two mutant alleles. The double mutant containing the AP2-A1 and AP2-D2 alleles had a much greater suppression of anther extrusion by reducing the lodicule size than the single AP2-D2 mutant, suggesting cumulative effects of the two mutant alleles. In addition, both single and double mutants exhibited compact spikes and shorter plant heights due to reduced rachis and culm internodes in the upper parts. The presence or absence of the wild-type AP2-B homoeolog had no significant effect on phenotype. This study provides insights into the cumulative effects of mutant AP2 alleles in suppressing open flowering and provides a basis for further research on the development of complete cleistogamy in hexaploid wheat.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11032-024-01458-9.

Identification of candidate genes responsible for chasmogamy in wheat

BACKGROUND

The flowering biology of wheat plants favours self-pollination which causes obstacles in wheat hybrid breeding. Wheat flowers can be divided into two groups, the first one is characterized by flowering and pollination within closed flowers (cleistogamy), while the second one possesses the ability to open flowers during processes mentioned above (chasmogamy). The swelling of lodicules is involved in the flowering of cereals and among others their morphology, calcium and potassium content differentiate between cleistogamic and non-cleistogamous flowers. A better understanding of the chasmogamy mechanism can lead to the development of tools for selection of plants with the desired outcrossing rate. To learn more, the sequencing of transcriptomes (RNA-Seq) and Representational Difference Analysis products (RDA-Seq) were performed to investigate the global transcriptomes of wheat lodicules in two highly chasmogamous (HCH, Piko and Poezja) and two low chasmogamous (LCH, Euforia and KWS Dacanto) varieties at two developmental stages-pre-flowering and early flowering.

RESULTS

The differentially expressed genes were enriched in five, main pathways: "metabolism", "organismal systems", "genetic information processing", "cellular processes" and "environmental information processing", respectively. Important genes with opposite patterns of regulation between the HCH and LCH lines have been associated with the lodicule development i.e. expression levels of MADS16 and MADS58 genes may be responsible for quantitative differences in chasmogamy level in wheat.

CONCLUSIONS

We conclude that the results provide a new insight into lodicules involvement in the wheat flowering process. This study generated important genomic information to support the exploitation of the chasmogamy in wheat hybrid breeding programs.

Phenotypic, Nutritional, and Antioxidant Characterization of Blanched Oenanthe javanica for Preferable Cultivar

Blanching is a technique used in blocking sunlight for the production of tender, sweet, and delicious stems in the field. This technique is also used in water dropwort (Oenanthe javanica), an important vegetable in East Asia. In China, the steamed stems of water dropwort are prepared with boiled rice. However, the effect of blanching on the nutritional level and antioxidant capacity of water dropwort has not been explored yet. The current study aims to determine the nutrient contents and antioxidant capacities of five cultivars and select the best cultivar. They were mainly compared in terms of phenotypic, physiological, nutritional, and antioxidant levels after blanch cultivation. Results indicate that blanching significantly influenced the phenotype, physiology, and nutritional level of water dropwort in all cultivars. Although few parameters decreased with blanching, starch, sugars, vitamins, minerals, and antioxidant activities increased significantly in the blanched stems in mid- and post-blanching periods. The most noticeable changes were detected in post-blanching samples. Furthermore, the best cultivar (V11E0012) was identified among them. Therefore, blanched water dropwort could be consumed for achieving more nutraceuticals and antioxidants, and cultivar V11E0012 could be recommend for blanching cultivation.