Mengqi Ding

Jasmonic acid/ethylene signaling coordinates hydroxycinnamic acid amides biosynthesis through ORA59 transcription factor

Hydroxycinnamic acid amides (HCAAs) are a class of antimicrobial metabolites involved in plant defense against necrotrophic pathogens, including Alternaria brassicicola and Botrytis cinerea. The agmatine coumaryl transferase (AtACT) is the key enzyme that catalyzes the last reaction in the biosynthesis of HCAAs, including p-coumaroylagmatine (CouAgm) and feruloylagmatine in Arabidopsis thaliana. However, the regulatory mechanism of AtACT gene expression is currently unknown. Yeast one-hybrid screening using the AtACT promoter as bait isolated the key positive regulator ORA59 that is involved in jasmonic acid/ethylene (JA/ET)-mediated plant defense responses. AtACT gene expression and HCAAs biosynthesis were synergistically induced by a combination of JA and ET. In the AtACT promoter, two GCC-boxes function equivalently for trans-activation by ORA59 in Arabidopsis protoplasts, and mutation of either GCC-box abolished AtACT mRNA accumulation in transgenic plants. Site-directed mutation analysis demonstrated that the specific Leu residue at position 228 of the ORA59 EDLL motif mainly contributed to its transcriptional activity on AtACT gene expression. Importantly, MEDIATOR25 (MED25) and ORA59 homodimer are also required for ORA59-dependent activation of the AtACT gene. These results suggest that ORA59 and two functionally equivalent GCC-boxes form the regulatory module together with MED25 that enables AtACT gene expression and HCAAs biosynthesis to respond to simultaneous activation of the JA/ET signaling pathways.

Comparative Analysis of Four Buckwheat Species Based on Morphology and Complete Chloroplast Genome Sequences

Buckwheat is a nutritional and economically crop belonging to Polygonaceae, Fagopyrum. To better understand the mutation patterns and evolution trend in the chloroplast (cp) genome of buckwheat, and found sufficient number of variable regions to explore the phylogenetic relationships of this genus, two complete cp genomes of buckwheat including Fagopyrum dibotrys (F. dibotrys) and Fagopyrum luojishanense (F. luojishanense) were sequenced, and other two Fagopyrum cp genomes were used for comparative analysis. After morphological analysis, the main difference among these buckwheat were height, leaf shape, seeds and flower type. F. luojishanense was distinguishable from the cultivated species easily. Although the F. dibotrys and two cultivated species has some similarity, they different in habit and component contents. The cp genome of F. dibotrys was 159,320 bp while the F. luojishanense was 159,265 bp. 48 and 61 SSRs were found in F. dibotrys and F. luojishanense respectively. Meanwhile, 10 highly variable regions among these buckwheat species were located precisely. The phylogenetic relationships among four Fagopyrum species based on complete cp genomes was showed. The results suggested that F. dibotrys is more closely related to Fagopyrum tataricum. These data provided valuable genetic information for Fagopyrum species identification, taxonomy, phylogenetic study and molecular breeding.

Germplasm Resources of Buckwheat in China

The history of Chinese buckwheat cultivation goes back to 1st and 2nd centuries BC. After thousands of years of cultivation and evolution, cultivated buckwheat is not only widely spread in China, but has also formed a number of varieties. Southwest China especially has plentiful resources of wild-type buckwheat, which has drawn the attention of the wider world. Until now, 27 buckwheat species have been named and reported in China, including 2 cultivated species and 25 wild species. They are widely distributed in Sichuan, Yunnan, Guizhou, and Tibet, in the southwest of China, because of the complicated geographical environments of these regions, which have been described as the treasure of plant resources. In the future, the relationship between buckwheat species and their genetic diversity will be further clarified, and there will be a sizable breakthrough in the area of breeding new varieties and exploiting new buckwheat resources.

Utilization of Wild Buckwheat Species

Abstract The roots, stems, leaves, flowers, and fruits of wild buckwheat are rich in proteins, amino acids, carbohydrates, minerals, flavanoids and other nutritional and medical composition, which have the efficacy of clearing heat and detoxicating, nourishing spleen and eliminating dampness, inhibiting the invasion of tumor cells and preventing and curing cardiovascular disease and diabetes. So the wild buckwheat is a kind of important resource plant that has the value of development and utilization.

Description of Cultivated Tartary Buckwheat

Abstract Tartary buckwheat is one of the cultivars of Fagopyrum , whose species name is Fagopyrum tataricum (L) Gaertn and whose English name is Tartary buckwheat. Tartary buckwheat is called phapar in India, tite phapar in Nepal, and bjo in Bhutan. In China and Nepal, it is also called bitter buckwheat. Tartary buckwheat is mainly grown in the south of China, India, the southern Himalayas, Nepal, Bhutan, and Pakistan, etc. The grains of Tartary buckwheat are rich in proteins, fats, vitamins, and minerals, as well as rutin, quercitin, and other flavonoids that other Gramineae crops don’t contain. Hence, Tartary buckwheat has considerable nutritional and medicinal values, which is considered as an ideal functional food source for humans.

Perennial Self-Incompatible Wild Fagopyrum Species

Abstract In this chapter, the botanical descriptions of Fagopyrum cymosum, Fagopyrum urophyllum, and Fagopyrum statice are presented, and the global distributions, habitats, and growth habits of these perennial self-incompatible wild Fagopyrum species are described. Fagopyrum cymosum has been known about for a long time, and its changing nomenclature throughout the years is also presented in the chapter.

Perennial Self-Compatible Wild Fagopyrum Species: F. hailuogouense

Abstract Fagopyrum hailuogouense is a perennial self-compatible wild Fagopyrum species. In this chapter, the botanical description, global distribution, habitat and growth habits of F. hailuogouense are described.

Description of Cultivated Common Buckwheat

Abstract Common buckwheat is the buckwheat cultivar that has the largest cultivated area and is the most widely distributed one in the world. The species name of common buckwheat is Fagopyrum esculentum Moench, while common buckwheat is its English name. Moreover, common buckwheat is also called “tian’qiao” in China and “mite phapar” in Nepal, which mean sweet buckwheat. Common buckwheat is an important crop in many countries that has become one of the human staples. People usually grind the fruits of common buckwheat (i.e., the achenes into flour, which is then processed into buckwheat noodles, buckwheat pancakes, and other pasta. Buckwheat groats that are processed from grains are the most widely used form, which is used to make porridge, soup, kasha, and other staples both in Europe and America. Moreover, common buckwheat is also one of the important nectar plants and relief crops.

Fagopyrum longzhoushanense , a new species of Polygonaceae from Sichuan, China

Fagopyrum longzhoushanense (Polygonaceae) is here described and illustrated as a new species from Longzhoushan (Puge County, Sichuan Province, China) on the basis of morphological, caryological and molecular analyses. The new species is morphologically similar to F. gracilipes from which it differs in having densely pubescent or villose parts, thicker and red-brown stems and branches, dense nodes, rugulose and small postulate leaf blade on the surface, stamens longer than pistils. Another similar species is F. densovillosum from which F. longzhoushanense differs by the winged and greater achenes, and the stamens which are longer than the pistils. From the caryioogical point of view F. longzhoushanense is a diploid species with 2n=2x=16 and a karyotype of 16 metacentric chromosomes, while F. gracilipes is tetraploid, 4n=4x=32, with a karyotype of 30 metacentric and 2 submetacentric chromosomes. The results of molecular marker analysis ( matK ) also highlight the distinction of the new species.

Cloning, expression, and in silico analysis of a novel annexin gene FtANX1 from Tartary buckwheat ( Fagopyrum tataricum (L.) Gaertn.)

Annexins are generally thought to play an essential role in the regulation of plant growth, development, and stress responses. Here we describe an annexin gene from Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.), designated as FtANX1. The full-length coding sequence of FtANX1 is 942 bp in size, encoding a polypeptide of 313 amino acids with a theoretical molecular mass of 36.0 kDa and pI 5.94. In silico analysis of the sequence revealed that FtANX1 contains four repeats, with a type-II Ca2+-binding site in repeat I. Expression pattern analysis provided evidence that FtANX1 was predominantly expressed in immature achenes, while its level was lowest in leaves. In addition, FtANX1 was found to be associated with stress responses in Tartary buckwheat, such as drought, cold, UV-B radiation, jasmonic acid, and heavy metals (Cu, Pb, Zn, and Cd). Several stress-related regulatory elements (ABRE, W-box, GATA-box, and CuRE elements) were found by in silico analysis in the FtANX1 promoter region. Our results showed that FtANX1, a novel annexin gene, may play an important role in the growth and stress tolerance of Tartary buckwheat.