The Role of EjSOC1s in Flower Initiation in Eriobotrya japonica

The MADS-box transcription factor SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) integrates environmental and endogenous signals to promote flowering in Arabidopsis. However, the role of SOC1 homologs in regulating flowering time in fruit trees remains unclear. To better understand the molecular mechanism of flowering regulation in loquat (Eriobotrya japonica Lindl.), two SOC1 homologs (EjSOC1-1 and EjSOC1-2) were identified and characterized in this work. Sequence analysis showed that EjSOC1-1 and EjSOC1-2 have conserved MADS-box and K-box domains. EjSOC1-1 and EjSOC1-2 were clearly expressed in vegetative organs, and high expression was detected in flower buds. As observed in paraffin-embedded sections, expression of the downstream flowering genes EjAP1s and EjLFYs started to increase at the end of June, a time when flower bud differentiation occurs. Additionally, high expression of EjSOC1-1 and EjSOC1-2 began 10 days earlier than that of EjAP1s and EjLFYs in shoot apical meristem (SAM). EjSOC1-1 and EjSOC1-2 were inhibited by short-day (SD) conditions and exogenous GA3, and flower bud differentiation did not occur after these treatments. EjSOC1-1 and EjSOC1-2 were found to be localized to the nucleus. Moreover, ectopic overexpression of EjSOC1-1 and EjSOC1-2 in wild-type Arabidopsis promoted early flowering, and overexpression of both was able to rescue the late flowering phenotype of the soc1-2 mutant. In conclusion, the results suggest that cultivated loquat flower bud differentiation in southern China begins in late June to early July and that EjSOC1-1 and EjSOC1-2 participate in the induction of flower initiation. These findings provide new insight into the artificial regulation of flowering time in fruit trees

Crustal thickness anomalies in the North Atlantic Ocean basin from gravity analysis

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 12 (2011): Q0AE02, doi:10.1029/2010GC003402.Gravity-derived crustal thickness models were calculated for the North Atlantic Ocean between 76°N and the Chain Fracture Zone and calibrated using seismically determined crustal thickness. About 7% of the ocean crust is 7 km thick and is interpreted to have been affected by excess magmatism. Thin crust probably reflects reduced melt production from relatively cold or refractory mantle at scales of up to hundreds of kilometers along the spreading axis. By far the most prominent thick crust anomaly is associated with Iceland and adjacent areas, which accounts for 57% of total crustal volume in excess of 7 km. Much smaller anomalies include the Azores (8%), Cape Verde Islands (6%), Canary Islands (5%), Madeira (<4%), and New England–Great Meteor Seamount chain (2%), all of which appear to be associated with hot spots. Hot spot–related crustal thickening is largely intermittent, suggesting that melt production is episodic on time scales of tens of millions of years. Thickened crust shows both symmetrical and asymmetrical patterns about the Mid-Atlantic Ridge (MAR) axis, reflecting whether melt anomalies were or were not centered on the MAR axis, respectively. Thickened crust at the Bermuda and Cape Verde rises appears to have been formed by isolated melt anomalies over periods of only ∼20–25 Myr. Crustal thickness anomalies on the African plate generally are larger than those on the North American plate; this most likely results from slower absolute plate speed of the African plate over relatively fixed hot spots.Supported by a fellowship from the China Scholarship Council. Additional support for this research was provided by the Charles D. Hollister Endowed Fund for Support of Innovative Research at WHOI (JL) and NSF China grants 40676023 and 40821062 (YJC)

Polyploidy underlies co-option and diversification of biosynthetic triterpene pathways in the apple tribe

Whole-genome duplication (WGD) plays important roles in plant evolution and function, yet little is known about how WGD underlies metabolic diversification of natural products that bear significant medicinal properties, especially in nonmodel trees. Here, we reveal how WGD laid the foundation for co-option and differentiation of medicinally important ursane triterpene pathway duplicates, generating distinct chemotypes between species and between developmental stages in the apple tribe. After generating chromosome-level assemblies of a widely cultivated loquat variety and Gillenia trifoliata, we define differentially evolved, duplicated gene pathways and date the WGD in the apple tribe at 13.5 to 27.1 Mya, much more recent than previously thought. We then functionally characterize contrasting metabolic pathways responsible for major triterpene biosynthesis in G. trifoliata and loquat, which pre- and postdate the Maleae WGD, respectively. Our work mechanistically details the metabolic diversity that arose post-WGD and provides insights into the genomic basis of medicinal properties of loquat, which has been used in both traditional and modern medicines

Analysis of major triterpene acids and total polysaccharides in the leaves of 11 species of

Loquat (Eriobotrya japonica) is a subtropical tree with commercially important fruit and with leaves that have medicinal uses against cough and asthma. Leaves contain significant amounts of phenols, flavonoids, triterpene acids, and polysaccharides. However, information of the triterpene acids and polysaccharides in leaves is limited. In this study, the contents of five major triterpene acids and total polysaccharides in the leaves of 11 species of Eriobotrya were determined using RP-HPLC and phenol-sulfuric acid method, respectively. Total concentration of triterpene acids varied from 8.38 to 22.35 mg g-1 DW. The concentration of triterpene acids was greater than 20 mg g-1 DW in E. bengalensis, E. prinoides and E. fragrans, and it was less than 10.0 mg g-1 DW in E. elliptica. Different drying temperature (40-80°C) of leaves did not affect the content of polysaccharides with highest content (80.8 mg g-1 DW) from E. prinoides. The contents of triterpene acid in six wild species and polysaccharides in 5 wild species were higher than that in cultivated loquat

Characterization of Carotenoid Accumulation and Carotenogenic Gene Expression During Fruit Development in Yellow and White Loquat Fruit

Accumulation of carotenoids in peel and pulp of the yellow-fleshed loquat ‘Zaozhong 6’ (ZZ6) and the white-fleshed loquat ‘Baiyu’ (BY) were tracked during different fruit development stages, and the expression of 15 carotenogenic genes were analyzed. During loquat fruit ripening the fresh weight content of β-carotene in peel and pulp of ZZ6 increased gradually and peaked at the fully ripe stage, reaching 68.53 µg⋅g−1 FW in the peel and 11.92 µg⋅g−1 FW in the pulp. In BY, the content of β-carotene in the peel increased and peaked at the fully ripe stage, reaching 38.89 µg⋅g−1 FW, while it decreased in the pulp from the original 0.47 µg⋅g−1 FW and reduced to 0.29 µg⋅g−1 FW. The content of β-cryptoxanthin in the peel and pulp of ZZ6 and BY both increased steadily, and peaked at the fully ripe stage; however, the content of lutein decreased in the peel of ZZ6 and increased in the pulp, but in BY, it dropped and then rose in the peel. There was no significant change of β-cryptoxanthin in the pulp of BY. After the breaker stage, the mRNA levels of phytoene synthase (PSY) and chromoplast-specific lycopene β-cyclase (CYCB) were higher in the peel, while CYCB and β-carotene hydroxylase (BCH) mRNAs were higher in the flesh of ZZ6, compared with BY. The results showed that the expression level of PSY, CYCB, and BCH appeared to cooperatively regulate the accumulation of carotenoids

Inter-specific and Inter-generic Hybridization Compatibility of Eriobotrya Species (Loquat) and Related Genera

We studied the cross-compatibility among 91 inter-specific combinations and 21 inter-generic combinations in 7 Eriobotrya plants and 2 related genera (Raphiolepis indica Lindl. and Photinia serrulata Lindl.) using emasculation, bagging, and artificial pollination. Our results showed that 28 of the 91 inter-specific combinations set no fruit, which means nearly 30% of the combinations were incompatible. In the remaining 63 combinations, most showed partial cross-compatibility, and a few showed complete cross compatibility. Eriobotrya plants were incompatible with plants from their related genera (R. indica Lindl. and P. serrulata Lindl.). Backcrossing produced 5 compatible combinations, which could set fruits and produce F1 progeny but only after embryo rescue. Fruit setting ratios varied among various species used as male or female parents. E. prinoides Rehd. & Wils., common loquat (E. japonica) and Eriobotrya × daduheensis, used as female parents resulted in an average fruit-setting ratio of 36.2%–58.2%. E. deflexa Nakai and its two forms, and E. elliptica Lindl. as female parents resulted in 2.9%–16.3% average fruit-setting ratio; however, the fruit set ratio was higher (22.4%–43.1%) if they were used as male parents. Failure of E. deflexa f. koshunensis Nakai × E. prinoides Rehd. & Wils. hybrids to set fruit could be attributed to sporophytic incompatibility

An Orthologous Epigenetic Gene Expression Signature Derived from Differentiating Embryonic Stem Cells Identifies Regulators of Cardiogenesis

<div><p>Here we used predictive gene expression signatures within a multi-species framework to identify the genes that underlie cardiac cell fate decisions in differentiating embryonic stem cells. We show that the overlapping orthologous mouse and human genes are the most accurate candidate cardiogenic genes as these genes identified the most conserved developmental pathways that characterize the cardiac lineage. An RNAi-based screen of the candidate genes in <i>Drosophila</i> uncovered numerous novel cardiogenic genes. shRNA knockdown combined with transcriptome profiling of the newly-identified transcription factors zinc finger protein 503 and zinc finger E-box binding homeobox 2 and the well-known cardiac regulatory factor NK2 homeobox 5 revealed that zinc finger E-box binding homeobox 2 activates terminal differentiation genes required for cardiomyocyte structure and function whereas zinc finger protein 503 and NK2 homeobox 5 are required for specification of the cardiac lineage. We further demonstrated that an essential role of NK2 homeobox 5 and zinc finger protein 503 in specification of the cardiac lineage is the repression of gene expression programs characteristic of alternative cell fates. Collectively, these results show that orthologous gene expression signatures can be used to identify conserved cardiogenic pathways.</p></div

ZNF503, ZEB2 and NKX2-5 are necessary for differentiation of CMs from human ESCs.

<p>(A) Flow cytometric analysis of cTnT expression on human ESCs after 10 days of differentiation along the cardiac lineage following shRNA knockdown of the indicated genes. Representative results of five experiments. WT cells were infected with a shRNA targeting GFP or empty vector, which yielded identical results as non-infected cells. (B) Hierarchical clustering of genes showing significant gene expression changes following shRNA knockdown of the indicated genes at the indicated time points. WT = wild-type; ZE = ZEB2 shRNA; ZN = ZNF503 shRNA; NK = NKX2-5 shRNA.</p