Transcriptional changes during ovule development in two genotypes of litchi (Litchi chinensis Sonn.) with contrast in seed size

Transcriptome analysis at mid-stage seed development in litchi with contrasting seed size

Litchi is a sub-tropical fruit crop with genotypes that bear fruits with variable seed size. Small seed size is a desirable trait in litchi, as it improves consumers' preference and facilitates fruit processing. Seed specific transcriptome analysis was performed in two litchi genotypes with contrasting seed size to identify the genes associated with seed development. The transcriptomic sequence data from seeds at mid-development stages (16-28 days after anthesis) were de-novo assembled into 1,39,608 Trinity transcripts. Out of these, 6325 transcripts expressed differentially between the two contrasting genotypes. Several putative genes for salicylic acid, jasmonic acid and brassinosteriod pathways were down-regulated in seeds of the small-seeded litchi. The putative regulators of seed maturation and seed storage were down-regulated in the small-seeded genotype. Embryogenesis, cell expansion, seed size and stress related Trinity transcripts exhibited differential expression. Further studies on gene characterization will reveal the early regulators of seed size in litchi.

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The online version contains supplementary material available at 10.1007/s13205-021-03098-8.

Identification of Finely Mapped Quantitative Trait Locus and Candidate Gene Mining for the Three-Seeded Pod Trait in Soybean

The three-seeded pod number is an important trait that positively influences soybean yield. Soybean variety with increased three-seeded pod number contributes to the seed number/plant and higher yield. The candidate genes of the three-seeded pod may be the key for improving soybean yield. In this study, identification and validation of candidate genes for three-seeded pod has been carried out. First, a total of 36 quantitative trait locus (QTL) were detected from the investigation of recombinant inbred lines including 147 individuals derived from a cross between Charleston and Dongning 594 cultivars. Five consensus QTLs were integrated. Second, an introgressed line CSSL-182 carrying the target segment for the trait from the donor parent was selected to verify the consensus QTL based on its phenotype. Third, a secondary group was constructed by backcrossing with CSSL-182, and two QTLs were confirmed. There were a total of 162 genes in the two QTLs. The mining of candidate genes resulted in the annotation of eight genes with functions related to pod and seed sets. Finally, haplotype analysis and quantitative reverse transcriptase real-time PCR were carried to verify the candidate genes. Four of these genes had different haplotypes in the resource group, and the differences in the phenotype were highly significant. Moreover, the differences in the expression of the four genes during pod and seed development were also significant. These four genes were probably related to the development process underlying the three-seeded pod in soybean. Herein, we discuss the past and present studies related to the three-seeded pod trait in soybean.

Metabolomic and transcriptomic profiling of three types of litchi pericarps reveals that changes in the hormone balance constitute the molecular basis of the fruit cracking susceptibility of Litchi chinensis cv. Baitangying

Many Litchi chinensis cv. Baitangying orchards are suffering from a serious fruit cracking problem, but few studies have improved our understanding of the mechanism or the molecular basis of cracking susceptibility in 'Baitangying'. We conducted metabolome and transcriptome analyses of three types of litchi pericarps. To prevent passive progression after fruit cracking from affecting the results, we mainly focused on 11 metabolites and 101 genes that showed the same regulatory status and overlap in pairwise comparisons of cracking 'Baitangying' versus noncracking 'Baitangying' and noncracking 'Baitangying' versus noncracking 'Feizixiao'. Compared with the cracking-resistant cultivar 'Feizixiao', the 'Baitangying' pericarp has higher abscisic acid contents, and the presence of relevant metabolites and genes suggests increased biosynthesis of ethylene and jasmonic acid and decreased auxin and brassinosteroid biosynthesis. The fruit cracking-susceptible trait in 'Baitangying' might be associated with differences in the balance of these five types of hormones between the pericarp of this cultivar and that of 'Feizixiao'. Additionally, combined analyses showed a correspondence between the metabolite profiles and transcript patterns. qRT-PCR validation indicated the reliability of our high-throughput results. The acquired information might help in further studying the mechanisms that mediate fruit cracking susceptibility in 'Baitangying' and other litchi cultivars.

Analysis of the molecular basis of fruit cracking susceptibility in Litchi chinensis cv. Baitangying by transcriptome and quantitative proteome profiling

Fruit cracking is a serious problem in Litchi chinensis cv. Baitangying orchards, but few advances have been made in understanding the molecular basis of cracking susceptibility in 'Baitangying'. In this work, we conducted transcriptome and quantitative proteome analyses of the pericarps of three kinds of litchi: noncracking 'Feizixiao' (cracking-resistant cultivar, F), noncracking 'Baitangying' (B), and cracking 'Baitangying' (CB). A total of 101 genes and 14 proteins with the same regulatory changes were found to overlap between CB vs. B and B vs. F, and we focused on these results to avoid the effects of passive progression after fruit cracking. The obtained data suggest that fruit cracking susceptibility in 'Baitangying' is related to pericarp photosynthetic characteristics and the oxidation of unsaturated fatty acids in this cultivar, which lead to changes in cuticle structure. Furthermore, differences in the pericarp hormone balance between 'Baitangying' and 'Feizixiao' may influence the susceptibility of 'Baitangying' to fruit cracking. This integrated analysis of transcriptomic and proteomic data indicates that susceptibility to fruit cracking in 'Baitangying' litchi is regulated both translationally and posttranslationally. Our results may help provide a new perspective for further study of the mechanisms that govern fruit cracking susceptibility in 'Baitangying' litchi and other fruits.

Effects of hMASP-2 on the formation of BCG infection-induced granuloma in the lungs of BALB/c mice

Tuberculosis, caused by Mycobacterium tuberculosis, affects the functions of the lung and causes high morbidity and mortality rates worldwide. MASP-2 is an executioner enzyme, which plays an essential role in the activation of lectin pathway. In our previous studies, the MASP-2 played a dual role in promoting the progress of lesions in BCG-infected rabbit skin models. However, the really effects of MASP-2 on tuberculosis are unknown. The aim of this study was to investigate the effects of MASP-2 in granuloma formation with BCG-infected mice. Compared to the control group, rAd-hMASP-2 treated group showed increasing in survival rate of BCG-infected mice (P = 0.042), and decreasing of bacteria loads (P = 0.005) in the lung tissue. MASP-2 displayed a protective efficacy in BCG-infected mice, which promoted the activation and recruitment of macrophages and lymphocytes to the granuloma. Moreover, the data obtained from the ELISA and RT-PCR demonstrated that mRNA expression for IL-6, CCL12, CCL2 and cytokines of IFN-γ, TNF-α in lung were significantly elevated by treatment of rAd-hMASP-2. Those findings provided an evidence that MASP-2 may be as a newly immunomodulatory in targeting granuloma formation, which displayed a potential protective role in control of tuberculosis.