Knockout of CAFFEOYL-COA 3-O-METHYLTRANSFERASE 6/6L enhances the S/G ratio of lignin monomers and disease resistance in Nicotiana tabacum.

Background: Nicotiana tabacum is an important economic crop, which is widely planted in the world. Lignin is very important for maintaining the physiological and stress-resistant functions of tobacco. However, higher lignin content will produce lignin gas, which is not conducive to the formation of tobacco quality. To date, how to precisely fine-tune lignin content or composition remains unclear. Results: Here, we annotated and screened 14 CCoAOMTs in Nicotiana tabacum and obtained homozygous double mutants of CCoAOMT6 and CCoAOMT6L through CRSIPR/Cas9 technology. The phenotype showed that the double mutants have better growth than the wild type whereas the S/G ratio increased and the total sugar decreased. Resistance against the pathogen test and the extract inhibition test showed that the transgenic tobacco has stronger resistance to tobacco bacterial wilt and brown spot disease, which are infected by Ralstonia solanacearum and Alternaria alternata, respectively. The combined analysis of metabolome and transcriptome in the leaves and roots suggested that the changes of phenylpropane and terpene metabolism are mainly responsible for these phenotypes. Furthermore, the molecular docking indicated that the upregulated metabolites, such as soyasaponin Bb, improve the disease resistance due to highly stable binding with tyrosyl-tRNA synthetase targets in Ralstonia solanacearum and Alternaria alternata. Conclusions: CAFFEOYL-COA 3-O-METHYLTRANSFERASE 6/6L can regulate the S/G ratio of lignin monomers and may affect tobacco bacterial wilt and brown spot disease resistance by disturbing phenylpropane and terpene metabolism in leaves and roots of Nicotiana tabacum, such as soyasaponin Bb.

Evaluation of Cooked Rice for Eating Quality and Its Components in Geng Rice.

At present, ''eating well" is increasingly desired by people instead of merely ''being full". Rice provides the majority of daily caloric needs for half of the global human population. However, eating quality is difficult to objectively evaluate in rice breeding programs. This study was carried out to objectively quantify and predict eating quality in Geng rice. First, eating quality and its components were identified by trained panels. Analysis of variance and broad-sense heritability showed that variation among varieties was significant for all traits except hardness. Among them, viscosity, taste, and appearance were significantly correlated with eating quality. We established an image acquisition and processing system to quantify cooked rice appearance and optimized the process of measuring cooked rice viscosity with a texture analyzer. The results show that yellow areas of the images were significantly correlated with appearance, and adhesiveness was significantly correlated with viscosity. Based on these results, multiple regression analysis was used to predict eating quality: eating quality = 0.37 × adhesiveness - 0.71 × yellow area + 0.89 × taste - 0.34, R2 = 0.85. The correlation coefficient between the predicted and actual values was 0.86. We anticipate that this predictive model will be useful in future breeding programs for high-eating-quality rice.

Deciphering the regulatory network of the NAC transcription factor FvRIF, a key regulator of strawberry (Fragaria vesca) fruit ripening.

The NAC transcription factor ripening inducing factor (RIF) was previously reported to be necessary for the ripening of octoploid strawberry (Fragaria × ananassa) fruit, but the mechanistic basis of RIF-mediated transcriptional regulation and how RIF activity is modulated remains elusive. Here, we show that FvRIF in diploid strawberry, Fragaria vesca, is a key regulator in the control of fruit ripening and that knockout mutations of FvRIF result in a complete block of fruit ripening. DNA affinity purification sequencing coupled with transcriptome deep sequencing suggests that 2,080 genes are direct targets of FvRIF-mediated regulation, including those related to various aspects of fruit ripening. We provide evidence that FvRIF modulates anthocyanin biosynthesis and fruit softening by directly regulating the related core genes. Moreover, we demonstrate that FvRIF interacts with and serves as a substrate of MAP kinase 6 (FvMAPK6), which regulates the transcriptional activation function of FvRIF by phosphorylating FvRIF at Thr-310. Our findings uncover the FvRIF-mediated transcriptional regulatory network in controlling strawberry fruit ripening and highlight the physiological significance of phosphorylation modification on FvRIF activity in ripening.

Biosynthesis and transport of pollen coat precursors in angiosperms.

The pollen coat is a hydrophobic mixture on the pollen grain surface, which plays an important role in protecting male gametes from various environmental stresses and microorganism attacks, and in pollen-stigma interactions during pollination in angiosperms. An abnormal pollen coat can result in humidity-sensitive genic male sterility (HGMS), which can be used in two-line hybrid crop breeding. Despite the crucial functions of the pollen coat and the application prospect of its mutants, few studies have focused on pollen coat formation. In this Review, the morphology, composition and function of different types of pollen coat are assessed. On the basis of the ultrastructure and development process of the anther wall and exine found in rice and Arabidopsis, the genes and proteins involved in the biosynthesis of pollen coat precursors and the possible transport and regulation process are sorted. Additionally, current challenges and future perspectives, including potential strategies utilizing HGMS genes in heterosis and plant molecular breeding, are highlighted.

The NAC transcription factors play core roles in flowering and ripening fundamental to fruit yield and quality.

Fruits are derived from flowers and play an important role in human food, nutrition, and health. In general, flowers determine the crop yield, and ripening affects the fruit quality. Although transcription factors (TFs) only account for a small part of plant transcriptomes, they control the global gene expression and regulation. The plant-specific NAC (NAM, ATAF, and CUC) TFs constitute a large family evolving concurrently with the transition of both aquatic-to-terrestrial plants and vegetative-to-reproductive growth. Thus, NACs play an important role in fruit yield and quality by determining shoot apical meristem (SAM) inflorescence and controlling ripening. The present review focuses on the various properties of NACs together with their function and regulation in flower formation and fruit ripening. Hitherto, we have a better understanding of the molecular mechanisms of NACs in ripening through abscisic acid (ABA) and ethylene (ETH), but how NACs regulate the expression of the inflorescence formation-related genes is largely unknown. In the future, we should focus on the analysis of NAC redundancy and identify the pivotal regulators of flowering and ripening. NACs are potentially vital manipulation targets for improving fruit quantity and quality.

A Clathrin-Related Protein, SCD2/RRP1, Participates in Abscisic Acid Signaling in Arabidopsis.

Abscisic acid (ABA) plays important roles in many aspects of plant growth and development, and responses to diverse stresses. Although much progress has been made in understanding the molecular mechanisms of ABA homoeostasis and signaling, the mechanism by which plant cells integrate ABA trafficking and signaling to regulate plant developmental processes is poorly understood. In this study, we used Arabidopsis STOMATAL CYTOKINESIS DEFECTIVE 2/RIPENING-REGULATED PROTEIN 1 (SCD2/RRP1) mutants and overexpression plants, in combination with transcriptome and protein-interaction assays, to investigate SCD2/RRP1 involvement in the integration of ABA trafficking and signaling in seed germination and seedling growth. Manipulation of SCD2/RRP1 expression affected ABA sensitivity in seed germination and seedling growth, as well as transcription of several ABA transporter genes and ABA content. RNA-sequencing analysis of Arabidopsis transgenic mutants suggested that SCD2/RRP1 was associated with ABA signaling via a type 2C protein phosphatase (PP2C) protein. The N- and C-terminal regions of SCD2/RRP1 separately interacted with both PYRABACTIN RESISTANCE 1 (PYR1) and ABA INSENSITIVE 1 (ABI1) on the plasma membrane, and SCD2/RRP1 acted genetically upstream of ABI1. Interestingly, ABA inhibited the interaction of SCD2/RRP1 with ABI1, but did not affect the interaction of SCD2/RRP1 with PYR1. These results suggested that in Arabidopsis SCD2/RRP1participates in early seed development and growth potentially through clathrin-mediated endocytosis- and clathrin-coated vesicle-mediated ABA trafficking and signaling. These findings provide insight into the mechanism by which cells regulate plant developmental processes through ABA.

Strawberry tonoplast transporter, FaVPT1, controls phosphate accumulation and fruit quality.

Phosphorus (P) is essential for plant growth and development, and the vacuole is an important organelle for phosphate storage. However, the tonoplast phosphate transporter in fleshy fruits remains unknown. In this study, based on the strawberry (Fragaria × ananassa) fruit transcriptome data, a tonoplast-localized vacuolar phosphate transporter with SPX and major facilitator superfamily domains, FaVPT1, was identified. FaVPT1 expression was highest in the fruits and could be induced by sucrose. Using transient transgenic systems in strawberry fruit, the downregulation and upregulation of FaVPT1 inhibited and promoted ripening, respectively, and affected phosphate contents, fruit firmness, sugar and anthocyanin contents, and ripening-related gene transcription. FaVPT1 could rescue Pi absorption in both yeast and the Arabidopsis atvpt1 mutant, confirming the similar function of FaVPT1 and AtVPT1, a previously identified tonoplast phosphate transporter in Arabidopsis. The Escherichia coli-expressed SPX domain of FaVPT1 could strongly bind to InsP6 with a Kd of 3.5 µM. The results demonstrate that FaVPT1 is a tonoplast phosphate transporter and regulates strawberry fruit ripening and quality, to a large extent, via sucrose.

Characterization of the hot pepper (Capsicum frutescens) fruit ripening regulated by ethylene and ABA.

BACKGROUND: Ripening of fleshy fruits has been classically defined as climacteric or non-climacteric. Both types of ripening are controlled by plant hormones, notably by ethylene in climacteric ripening and by abscisic acid (ABA) in non-climacteric ripening. In pepper (Capsicum), fruit ripening has been widely classified as non-climacteric, but the ripening of the hot pepper fruit appears to be climacteric. To date, how to regulate the hot pepper fruit ripening through ethylene and ABA remains unclear. RESULTS: Here, we examined ripening of the hot pepper (Capsicum frutescens) fruit during large green (LG), initial colouring (IC), brown (Br), and full red (FR) stages. We found a peak of ethylene emission at the IC stage, followed by a peak respiratory quotient at the Br stage. By contrast, ABA levels increased slowly before the Br stage, then increased sharply and reached a maximum level at the FR stage. Exogenous ethylene promoted colouration, but exogenous ABA did not. Unexpectedly, fluridone, an inhibitor of ABA biosynthesis, promoted colouration. RNA-sequencing data obtained from the four stages around ripening showed that ACO3 and NCED1/3 gene expression determined ethylene and ABA levels, respectively. Downregulation of ACO3 and NCED1/3 expression by virus-induced gene silencing (VIGS) inhibited and promoted colouration, respectively, as evidenced by changes in carotenoid, ABA, and ethylene levels, as well as carotenoid biosynthesis-related gene expression. Importantly, the retarded colouration in ACO3-VIGS fruits was rescued by exogenous ethylene. CONCLUSIONS: Ethylene positively regulates the hot pepper fruit colouration, while inhibition of ABA biosynthesis promotes colouration, suggesting a role of ABA in de-greening. Our findings provide new insights into processes of fleshy fruit ripening regulated by ABA and ethylene, focusing on ethylene in carotenoid biosynthesis and ABA in chlorophyll degradation.

A leu-rich repeat receptor-like protein kinase, FaRIPK1, interacts with the ABA receptor, FaABAR, to regulate fruit ripening in strawberry.

Strawberry (Fragaria×ananassa) is a model plant for studying non-climacteric fruit ripening regulated by abscisic acid (ABA); however, its exact molecular mechanisms are yet not fully understood. In this study, a predicted leu-rich repeat (LRR) receptor-like kinase in strawberry, red-initial protein kinase 1 (FaRIPK1), was screened and, using a yeast two-hybrid assay, was shown to interact with a putative ABA receptor, FaABAR. This association was confirmed by bimolecular fluorescence complementation and co-immunoprecipitation assays, and shown to occur in the nucleus. Expression analysis by real-time PCR showed that FaRIPK1 is expressed in roots, stems, leaves, flowers, and fruit, with a particularly high expression in white fruit at the onset of coloration. Down-regulation of FaRIPK1 expression in strawberry fruit, using Tobacco rattle virus-induced gene silencing, inhibited ripening, as evidenced by suppression of ripening-related physiological changes and reduced expression of several genes involved in softening, sugar content, pigmentation, and ABA biosynthesis and signaling. The yeast-expressed LRR and STK (serine/threonine protein kinase) domains of FaRIPK1 bound ABA and showed kinase activity, respectively. A fruit disc-incubation test revealed that FaRIPK1 expression was induced by ABA and ethylene. The synergistic action of FaRIPK1 with FaABAR in regulation of strawberry fruit ripening is discussed.

[Anatomic investigation of the pedicle fat grafts with the third lumbar segmental artery and its application in reoperation for lumbar disc herniation].

OBJECTIVE: To investigate the blood supply of the pedicle fat grafts with the third lumbar segmental artery and its clinical effects on reoperation for lumbar disc herniation. METHODS: Twelve sides of 6 adult cadaver examples were contributed to investigate the courser of lumbar segmental vessels and the distribution of hypodermic capillary net of the dorsal branch of the third lumbar segmental artery. From January 2000 to January 2007,49 patients needed reoperation to treat lumbar disc herniation,including 26 males and 23 females with an average age of 55.6 years (ranged from 39 to 70 years). Duration between two operations ranged from 8 months to 15 years with an average of 6.9 years. Reoperative reasons included recurrent lumbar disc protrusion(30 cases)postoperative epidural scar formation (17 cases), postoperative epidural cyst formation (2 cases). Of them,9 patients underwent posterior lumbar interbody fusion at the second operation. The pedicle fat grafts with the third lumbar segmental artery were covered on the sites of the laminectomy in these patients. After negative pressure drainage tube were pulled out, 2 ml Chitsan were injected to the sites of the laminectomy and around epidural nerve root through epidural catheter. VAS score and the Oswestry Disability Index (ODI) were used to assess clinical outcomes before and after operation. RESULTS: The courser of third lumbar segmental vessels were invariant at the lateral face of the lumbar vertebral body. The dorsal branch of the third lumbar segmental artery penetrated thoracolumbar fascia and formed rich hypodermic capillary net in the region. All patients were followed up from 5 to 8 years with an average of 5.6 years. VAS score of low back pain and leg pain decreased respectively from preoperative 7.6 +/- 1.2, 8.9 +/- 0.9 to 3.6 +/- 0.5, 3.0 +/- 0.4 at final follow-up (P < 0.01); and ODI score decreased from preoperative 44.1 +/- 6.2 to 13.9 +/- 3.6 at final follow-up (P < 0.01). According to ODI score to evaluate the clinical outcomes, 29 cases got excellent results, 11 good, 7 fair, 2 poor. CONCLUSION: The pedicle fat grafts with the third lumbar segmental artery and Chitsan can reduce epidural scar formation and prevent peridural fibrosis and adhesion and improve clinical effects of reoperation for lumbar disc herniation.