An R2R3 MYB transcription factor confers brown planthopper resistance by regulating the phenylalanine ammonia-lyase pathway in rice.

Brown planthopper (BPH) is one of the most destructive insects affecting rice (Oryza sativa L.) production. Phenylalanine ammonia-lyase (PAL) is a key enzyme involved in plant defense against pathogens, but the role of PAL in insect resistance is still poorly understood. Here we show that expression of the majority of PALs in rice is significantly induced by BPH feeding. Knockdown of OsPALs significantly reduces BPH resistance, whereas overexpression of OsPAL8 in a susceptible rice cultivar significantly enhances its BPH resistance. We found that OsPALs mediate resistance to BPH by regulating the biosynthesis and accumulation of salicylic acid and lignin. Furthermore, we show that expression of OsPAL6 and OsPAL8 in response to BPH attack is directly up-regulated by OsMYB30, an R2R3 MYB transcription factor. Taken together, our results demonstrate that the phenylpropanoid pathway plays an important role in BPH resistance response, and provide valuable targets for genetic improvement of BPH resistance in rice.

Comparative Metabolomic and Transcriptomic Analyses of Phytochemicals in Two Elite Sweet Potato Cultivars for Table Use.

To elucidate nutritional components in sweet potato cultivars for table use and to compare the phytochemicals of cultivars from different countries, 'Kokei No. 14' and 'Xinxiang' were selected. The physiological parameters and metabolites were determined using the colorimetric method and widely targeted metabolomics, respectively. Transcriptomic analysis was performed to explain the mechanism that resulted in phytochemical differences. 'Xinxiang' showed higher flavonoid and carotenoid contents. Metabolomics showed five upregulated flavonoids. Two essential amino acids (EAAs) and one conditionally essential amino acid (CEAA) were upregulated, whereas four EAAs and two CEAAs were downregulated. Unlike lipids, in which only one of thirty-nine was upregulated, nine of twenty-seven differentially accumulated phenolic acids were upregulated. Three of the eleven different alkaloids were upregulated. Similarly, eight organic acids were downregulated, with two upregulated. In addition, three of the seventeen different saccharides and alcohols were upregulated. In 'other metabolites,' unlike vitamin C, 6'-O-Glucosylaucubin and pantetheine were downregulated. The differentially accumulated metabolites were enriched to pathways of the biosynthesis of secondary metabolites, ABC transporters, and tyrosine metabolism, whereas the differentially expressed genes were mainly concentrated in the metabolic pathway, secondary metabolite biosynthesis, and transmembrane transport functions. These results will optimize the sweet potato market structure and enable a healthier diet for East Asian residents.

Comparative analysis of chloroplast genomes of cultivars and wild species of sweetpotato (Ipomoea batatas [L.] Lam).

BACKGROUND: Sweetpotato (Ipomoea batatas [L.] Lam.) is an important food crop. However, the genetic information of the nuclear genome of this species is difficult to determine accurately because of its large genome and complex genetic background. This drawback has limited studies on the origin, evolution, genetic diversity and other relevant studies on sweetpotato. RESULTS: The chloroplast genomes of 107 sweetpotato cultivars were sequenced, assembled and annotated. The resulting chloroplast genomes were comparatively analysed with the published chloroplast genomes of wild species of sweetpotato. High similarity and certain specificity were found among the chloroplast genomes of Ipomoea spp. Phylogenetic analysis could clearly distinguish wild species from cultivars. Ipomoea trifida and Ipomoea tabascana showed the closest relationship with the cultivars, and different haplotypes of ycf1 could be used to distinguish the cultivars from their wild relatives. The genetic structure was analyzed using variations in the chloroplast genome. Compared with traditional nuclear markers, the chloroplast markers designed based on the InDels on the chloroplast genome showed significant advantages. CONCLUSIONS: Comparative analysis of chloroplast genomes of 107 cultivars and several wild species of sweetpotato was performed to help analyze the evolution, genetic structure and the development of chloroplast DNA markers of sweetpotato.

Construction of high-density genetic map based on SLAF-seq and QTL analysis of major traits in sweetpotato [Ipomoea batatas (L.) Lam.].

Sweetpotato, Ipomoea batatas (L.) Lam., is an important worldwide crop used as feed, food, and fuel. However, its polyploidy, high heterozygosity and self-incompatibility makes it difficult to study its genetics and genomics. Longest vine length (LVL), yield per plant (YPP), dry matter content (DMC), starch content (SC), soluble sugar content (SSC), and carotenoid content (CC) are some of the major agronomic traits being used to evaluate sweetpotato. However limited research has actually examined how these traits are inherited. Therefore, after selecting 212 F1 from a Xin24 × Yushu10 crossing as the mapping population, this study applied specific-locus amplified fragment sequencing (SLAF-seq), at an average sequencing depth of 26.73 × (parents) and 52.25 × (progeny), to detect single nucleotide polymorphisms (SNPs). This approach generated an integrated genetic map of length 2441.56 cM and a mean distance of 0.51 cM between adjacent markers, encompassing 15 linkage groups (LGs). Based on the linkage map, 26 quantitative trait loci (QTLs), comprising six QTLs for LVL, six QTLs for YPP, ten QTLs for DMC, one QTL for SC, one QTL for SSC, and two QTLs for CC, were identified. Each of these QTLs explained 6.3-10% of the phenotypic variation. It is expected that the findings will be of benefit for marker-assisted breeding and gene cloning of sweetpotato.

Isolation, characterization, and functional verification of salt stress response genes of NAC transcription factors in Ipomoea pes-caprae.

Adverse environmental stress is a major environmental factor threatening food security, which is why improving plant stress resistance is essential for agricultural productivity and environmental sustainability. The NAC (NAM, ATAF, and CUC) transcription factors (TFs) play a dominant role in plant responses to abiotic and biotic stresses, but they have been poorly studied in Ipomoea pes-caprae. In this research, 12 NAC TFs, named IpNAC1-IpNAC12, were selected from transcriptome data. The homologous evolution tree divided IpNACs into four major categories, and six IpNACs were linearly associated with Arabidopsis ANAC genes. From the gene structures, protein domains, and promoter upstream regulatory elements, IpNACs were shown to contain complete NAC-specific subdomains (A-E) and cis-acting elements corresponding to different stress stimuli. We measured the expression levels of the 12 IpNACs under abiotic stress (salt, heat, and drought) and hormone treatment (abscisic acid, methyl jasmonate, and salicylic acid), and their transcription levels differed. IpNAC5/8/10/12 were located in the nucleus through subcellular localization, and the overexpressing transgenic Arabidopsis plants showed high tolerance to salt stress. The cellular Na+ homeostasis content in the mature and elongation zones of the four IpNAC transgenic sweetpotato roots showed an obvious efflux phenomenon. These conclusions demonstrate that IpNAC5/8/10/12 actively respond to abiotic stress, have significant roles in improving plant salt tolerance, and are important salt tolerance candidate genes in I. pes-caprae and sweetpotato. This study laid the foundation for further studies on the function of IpNACs in response to abiotic stress. It provides options for improving the stress resistance of sweetpotato using gene introgression from I. pes-caprae.

Resequencing of sweetpotato germplasm resources reveals key loci associated with multiple agronomic traits.

Sweetpotato is an important crop that exhibits hexaploidy and high heterozygosity, which limits gene mining for important agronomic traits. Here, 314 sweetpotato germplasm resources were deeply resequenced, and 4 599 509 SNPs and 846 654 InDels were generated, among which 196 124 SNPs were nonsynonymous and 9690 InDels were frameshifted. Based on the Indels, genome-wide marker primers were designed, and 3219 of 40 366 primer pairs were selected to construct the core InDel marker set. The molecular ID of 104 sweetpotato samples verified the availability of these primers. The sweetpotato population structures were then assessed through multiple approaches using SNPs, and diverse approaches demonstrated that population stratification was not obvious for most Chinese germplasm resources. As many as 20 important agronomic traits were evaluated, and a genome-wide association study was conducted on these traits. A total of 19 high-confidence loci were detected in both models. These loci included several candidate genes, such as IbMYB1, IbZEP1, and IbYABBY1, which might be involved in anthocyanin metabolism, carotenoid metabolism, and leaf morphogenesis, respectively. Among them, IbZEP1 and IbYABBY1 were first reported in sweetpotato. The variants in the promoter and the expression levels of IbZEP1 were significantly correlated with flesh color (orange or not orange) in sweetpotato. The expression levels of IbYABBY1 were also correlated with leaf shape. These results will assist in genetic and breeding studies in sweetpotato.

Metabolomic and Transcriptomic Analyses of the Flavonoid Biosynthetic Pathway for the Accumulation of Anthocyanins and Other Flavonoids in Sweetpotato Root Skin and Leaf Vein Base.

Sweetpotato [Ipomoea batatas (L.) Lam.] is a major tuberous root crop that is rich in flavonoids. Here, we discovered a spontaneous mutation in the color of the leaf vein base (LVB) and root skin (RS) in the Zheshu 81 cultivar. The flavonoid and anthocyanin metabolites and molecular mechanism were analyzed using metabolome and transcriptome data. Compared to the wild type, 13 differentially accumulated metabolites (DAMs) in the LVB and 59 DAMs in the RS were all significantly downregulated. Moreover, all the anthocyanin metabolites decreased significantly. The differentially expressed genes (DEGs) encoding the key enzymes in the later enzymatic reaction of anthocyanin and flavonoid were significantly downregulated in the mutant. The expression trends of the transcription factor MYB were evidently related to the anthocyanin content. These results offer insights into the coloration in the LVB and RS and a theoretical basis for determining the regulation of flavonoid and anthocyanin synthesis in sweetpotato.

[Effectiveness comparison of LARS artificial ligament and autogenous hamstring tendon in one-stage reconstruction of anterior and posterior cruciate ligaments].

OBJECTIVE: To compare the effectiveness of arthroscopic one-stage reconstruction of anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) with LARS artificial ligament and autogenous hamstring tendon, respectively. METHODS: A retrospective study was performed on 23 patients with ACL and PCL injuries, who were treated with one-stage reconstruction, between June 2013 and June 2017. The ACL and PCL were reconstructed with LARS artificial ligament in 11 patients (artificial ligament group) and autogenous hamstring tendon in 12 patients (autogenous tendon group). There was no significant difference in gender, age, side of injury, cause of injury, time from injury to operation, and preoperative Lysholm score and International Knee Documentation Committee (IKDC) score between the two groups ( P>0.05). The operation time, the time of recovery of daily activities and preoperative exercise level, the occurrence of surgical-related complications, Lysholm score, IKDC score, and the results of knee stability assessment were recorded and compared between the two groups. RESULTS: The operation time and the time of recovery of daily activities and preoperative exercise level were significantly shorter in artificial ligament group than in autogenous tendon group ( P<0.05). All incisions healed primarily. In autogenous tendon group, the common fibular nerve injury occurred in 1 case and intermuscular vein thrombosis occurred in 1 case. No complication occurred in the remaining patients of the two groups. All the patients were followed up 24-54 months (mean, 36.4 months). At last follow-up, the Lysholm score and IKDC score of the two groups were significantly higher than preoperative scores ( P<0.05). There was no significant difference between the two groups ( P>0.05). The varus and valgus stress tests of the two groups were negative. There was no significant difference in anterior drawer test, posterior drawer test, and Lachman test between the two groups ( P>0.05). CONCLUSION: The effectiveness of arthroscopic one-stage reconstruction of ACL and PCL with LARS artificial ligament or autogenous hamstring tendon was similar. The knee function and stability recover well. But the patients with LARS artificial ligament reconstruction can resume daily activities and return to exercise earlier.

[Two-stage reverse total shoulder arthroplasty for treating postoperative deep infection after internal fixation of proximal humeral fracture].

OBJECTIVE: To summarize the effectiveness of two-stage reverse total shoulder arthroplasty for treating postoperative deep infection after internal fixation of the proximal humeral fracture. METHODS: Between June 2014 and January 2018, 17 patients with deep infection and humeral head necrosis or bone nonunion after internal fixation of proximal humeral fractures were treated. There were 8 males and 9 females, aged from 52 to 78 years (mean, 63.8 years). The infection occurred at 19-66 months after the initial internal fixation (mean, 34.8 months). Microbial culture of joint fluid was positive in 14 cases and negative in 3 cases. The preoperative Constant score, American shoulder and elbow surgeons (ASES) score, and visual analogue scale (VAS) score were 36.41±8.65, 31.06±7.43, and 7.29±0.99, respectively. The preoperative ranges of forward flexion, abduction, external rotation were (45.88±12.46), (42.18±12.31), and (16.76±4.92)°, respectively. The preoperative range of internal rotation was buttock in 9 cases, lumbosacral joint in 3 cases, L 3 in 5 cases. At the first-stage surgery, the thorough debridement was done and the antibiotic-impregnated bone cement spacer was placed after the removal of internal fixation. After the infections disappeared, the two-stage reverse total shoulder arthroplasty was performed. The mean interval between the two procedures was 4.2 months (range, 3.0-6.5 months). RESULTS: All the incisions healed primarily and no complications such as recurrent infection or vascular nerve injury occurred. All patients were followed up 15-32 months (mean, 22.0 months). At last follow-up, the ranges of forward flexion, abduction, and external rotation were (109.00±23.66), (98.53±16.92), (41.41±6.82)°, respectively; and the range of internal rotation was lumbosacral joint in 5 cases, L 3 in 8 cases, T 12 in 4 cases. The range of motion of shoulder joints at last follow-up was significant improved when compared with the preoperative range of motion ( P<0.05). The Constant score (64.88±8.70), ASES score (65.18±8.10), and VAS score (2.94±1.25) were significantly superior to the preoperative scores ( P<0.05). X-ray films showed that no prosthesis loosening occurred. CONCLUSION: Two-stage reverse total shoulder arthroplasty is an effective treatment for the postoperative deep infection after internal fixation of the proximal humeral fracture, which has advantages of low risk of infection recurrence, good shoulder function, and satisfactory short-term effectiveness.

RNA-seq reveals the salt tolerance of Ipomoea pes-caprae, a wild relative of sweet potato.

Wild relatives of crops are often rich in genetic resources and provide great possibilities for crop improvement. Ipomoea pes-caprae is one of the wild relatives of sweet potato and has high salt tolerance. Transcriptomes in the treatment and control groups at various times were sequenced to identify salt tolerance genes and salt response pathways. A total of 40,525 genes were obtained, of which 2478 and 3334 were differentially expressed in the roots and leaves of I. pes-caprae under salt stress, respectively. Identification of candidate genes revealed that the mitogen-activated protein kinase (MAPK) signaling pathway of plants and plant hormone signal transduction participates in the salt signal of I. pes-caprae under salt stress. Homology to ABI2 (HAB2) and Clade A protein phosphatases type 2C (HAI1), which encode two protein phosphatases 2C (PP2C) in the abscisic acid (ABA) signal pathway, were continuously up-regulated upon salt stress, indicating their key role in the salt signal transduction pathway of I. pes-caprae. The expression of EIN3-binding F-box protein 1 (EBF1) in the ethylene signaling pathway was also up-regulated, revealing that the salt tolerance of I. pes-caprae was related to the scavenging of reactive oxygen species (ROS). This study provides insights into the mechanism of salt-tolerant plants and the mining of salt-tolerant genes in sweet potato for the innovation of germplasm resources.

Preparation of multi-shelled conductive polymer hollow microspheres by using Fe3O4 hollow spheres as sacrificial templates.

Multi-shelled conductive polymer hollow microspheres were successfully generated by using Fe3O4 hollow microspheres as sacrificial templates via a programmed reaction-temperature process. Moreover, the multi-shelled PEDOT microspheres exhibited superb microwave absorption performance.

Conductive polyaniline helixes self-assembled in the absence of chiral dopant.

The morphological evolution of PANI helixes was achieved without the use of chiral dopants, but by a facile process through the generation of onion-like multi-lamellar vesicles used as a novel soft-template and a liquid crystal acting as a promoter for PANI polymerization and self-assembly, which is a breakthrough for the synthesis of helical structures.