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Ca2+-ATPases have been confirmed to play very important roles in plant growth and development and in stress responses. However, studies on banana (Musa acuminata) Ca2+-ATPases are very limited. In this study, we identified 18 Ca2+-ATPase genes from banana, including 6 P-IIA or ER (Endoplasmic Reticulum) type Ca2+-ATPases (MaEACs) and 12 P-IIB or Auto-Inhibited Ca2+-ATPases (MaACAs). The MaEACs and MaACAs could be further classified into two and three subfamilies, respectively. This classification is well supported by their gene structures, which are encoded by protein motif distributions. The banana Ca2+-ATPases were all predicted to be plasma membrane-located. The promoter regions of banana Ca2+-ATPases contain many cis-acting elements and transcription factor binding sites (TFBS). A gene expression analysis showed that banana Ca2+-ATPases were differentially expressed in different organs. By investigating their expression patterns in banana roots under different concentrations of Ca2+ treatments, we found that most banana Ca2+-ATPase members were highly expressed under 4 mM and 2 mM Ca2+ treatments, but their expression decreased under 1 mM and 0 mM Ca2+ treatments, suggesting that their downregulation might be closely related to reduced Ca accumulation and retarded growth under low Ca2+ and Ca2+ deficiency conditions. Our study will contribute to the understanding of the roles of Ca2+-ATPases in banana growth and Ca management. [ABSTRACT FROM AUTHOR]

This study compared the physicochemical and functional properties of starches from eight cultivars of avocado seeds. Amylose content, morphology, crystalline structure, swelling power, solubility, thermal and pasting properties, and in vitro digestibility were investigated. The results revealed that the apparent amylose content of starches from avocado seeds varied with different varieties. Light microscopic and scanning electron microscopic examination demonstrated that the eight starches differed slightly in terms of morphology and granule size. The X-ray diffraction and Fourier transform infrared spectroscopy analyses showed that the crystal structure and chemical linkage of the avocado seed starches were similar. However, the pasting, water solubility, and thermal properties of the eight avocado seed starches differed. Importantly, all the starches had high resistant starch content (>60%), with the highest found in Hass seeds (77.83%). To conclude, starch from avocado seeds has a high potential for use in the production of resistant starch. [ABSTRACT FROM AUTHOR]

Accumulated evidence has revealed the mitigation effects of exogenous melatonin on cold stress in plants. In this study, to investigate the defensive roles of exogenous melatonin in banana under cold stress, we researched the influences of exogenous melatonin on the chlorophyll fluorescence parameters, antioxidant defense indexes and expression levels of cold-responsive genes in cold-stressed 'Brazil' banana seedlings. Results showed that 100 μM of exogenous melatonin achieved the best cold-resistance-promoting effect in banana. Exogenous melatonin treatment significantly increased the electron transfer rate, light harvesting efficiency, total antioxidant capacity, catalase and superoxidase activities and proline and soluble sugar contents and significantly reduced the accumulations of malondialdehyde, superoxide anion and hydrogen peroxide in the leaves of cold-stressed banana. In addition, under cold stress, melatonin significantly induced the expression of low-temperature-responsive genes, such as MaChiI1, MaCSD1C, MaWhy1, MaKIN10, MaADA1 and MaHOS1. It was concluded that the application of exogenous melatonin enhanced antioxidant defense and induced the expression of cold-responsive genes, thereby improving the cold resistance of banana. Our study will provide a basis for the application of exogenous melatonin in improving plant cold resistance. [ABSTRACT FROM AUTHOR]

Banana is a major fruit crop grown in tropical and subtropical regions worldwide. Among cultivars, "FenJiao, FJ" (Musa spp. ABB, Pisang Awak subgroup) is a popular variety of bananas, due to its better sugar-acid blend and relatively small fruit shape. However, because the traditional FJ variety grows relatively high in height, it is vulnerable to lodging and unsuitable for harvesting. In this study, we sought desirable banana mutants by carrying out ethyl methanesulfonate (EMS) mutagenesis with the FJ cultivar. After the FJ shoot tips had been treated with 0.8% (v/v) EMS for 4 h, we obtained a stably inherited mutant, here called " ReFen 1 " (RF1), and also observed a semi-dwarfing phenotype. Compared with the wild type (FJ), this RF1 mutant featured consistently improved agronomic traits during 5-year field experiments conducted in three distinct locations in China. Notably, the RF1 plants showed significantly enhanced cold tolerance and Sigatoka disease resistance, mainly due to a substantially increased soluble content of sugar and greater starch accumulation along with reduced cellulose deposition. Therefore, this study not only demonstrated how a powerful genetic strategy can be used in fruit crop breeding but also provided insight into the identification of novel genes for agronomic trait improvement in bananas and beyond. [ABSTRACT FROM AUTHOR]

We assembled the complete chloroplast genome of Heracleum millefolium which is a traditional widely used medicinal plant in China. The whole genome is 150,025 bp in length which was divided into four subregions: a large single-copy region (93,645 bp), a pair of 19,458 bp inverted repeats regions, and a small single-copy region (17,464 bp), respectively. Additionally, the chloroplast genome of H. millefolium detected 128 genes, including 85 protein coding genes, 36 transfer RNAs, and eight ribosomal RNAs. The overall GC content of this chloroplast genome is 37.5% and the mean coverage value is 1752.4x. Phylogenetic analysis based on 17 chloroplast genomes dataset was conducted to clarify the relationships of the major clades in Apiaceae. The results strongly supported the monophyly of Heracleum and the closer relationship of H. millefolium and H. candicans. [ABSTRACT FROM AUTHOR]

Plant aquaporins (AQPs) are subdivided into eight groups: PIPs, NIPs, GIPs, HIPs, XIPs, LIPs, TIPs, and SIPs. However, the genetic function and physiological mechanisms of the SIP group in abiotic stress response in plants remains unknown. In this study, we cloned and characterized a banana SIP group AQP gene, designated MaSIP2-1. MaSIP2-1 showed upregulation after osmotic, salt, and cold treatments. Overexpression of MaSIP2-1 in bananas resulted in smaller leaf area and lower plant height than wild-type (WT) plants under normal growth conditions. Lines over-expressing MaSIP2-1 showed increased tolerance to drought and cold stresses, demonstrating that transgenic lines had higher content of chlorophyll, proline, soluble sugar, and abscisic acid (ABA), but lower levels of ion leakage (IL), malondialdehyde (MDA), H2O2, and gibberellins (GAs), than WT after drought, cold, and recovery conditions. Moreover, transgenic lines had higher expression of ABA biosynthetic and responsive genes than WT under drought and cold conditions. Taken together, our results show that MaSIP2-1 plays a positive role in dwarfing and tolerance to drought and cold stresses through improved osmotic adjustment, less membrane injury, and changes in ABA and GA levels. Therefore, MaSIP2-1 has the potential for utilization to improve abiotic stress tolerance in crop breeding. [ABSTRACT FROM AUTHOR]

Keywords: " ReFen 1 " mutant; Pisang Awak (ABB); ethyl methanesulfonate (EMS)-mutagenesis; semi-dwarfing; agronomic traits; cold tolerance; sigatoka disease resistance; banana breeding EN " ReFen 1 " mutant Pisang Awak (ABB) ethyl methanesulfonate (EMS)-mutagenesis semi-dwarfing agronomic traits cold tolerance sigatoka disease resistance banana breeding 1 1 1 11/12/21 20211108 NES 211108 In the published article, there was an error regarding the order of funding agencies as listed in the Funding statement. Pisang Awak (ABB), " ReFen 1 " mutant, ethyl methanesulfonate (EMS)-mutagenesis, semi-dwarfing, agronomic traits, cold tolerance, sigatoka disease resistance, banana breeding ABB, Pisang Awak Subgroup) for Improved Agronomic Traits and Enhanced Cold Tolerance and Disease Resistance. [Extracted from the article]

Exposure of banana plants, one of the most important tropical and subtropical plants, to low temperatures causes a severe drop in productivity, as they are sensitive to cold and do not have a strong defense system against chilling. Therefore, this study aimed to improve the growth and resistance to cold stress of banana plants using foliar treatments of chitosan nanoparticles (CH-NPs). CH-NPs produced by nanotechnology have been used to enhance tolerance and plant growth under different abiotic stresses, e.g., salinity and drought; however, there is little information available about their effects on banana plants under cold stress. In this study, banana plants were sprayed with four concentrations of CH-NPs—i.e., 0, 100, 200, and 400 mg L−1 of deionized water—and a group that had not been cold stressed or undergone CH-NP treatment was used as control. Banana plants (Musa acuminata var. Baxi) were grown in a growth chamber and exposed to cold stress (5 °C for 72 h). Foliar application of CH-NPs caused significant increases (p < 0.05) in most of the growth parameters and in the nutrient content of the banana plants. Spraying banana plants with CH-NPs (400 mg L−1) increased the fresh and dry weights by 14 and 41%, respectively, compared to the control. A positive correlation was found between the foliar application of CH-NPs, on the one hand, and photosynthesis pigments and antioxidant enzyme activities on the other. Spraying banana plants with CH-NPs decreased malondialdehyde (MDA) and reactive oxygen species (ROS), i.e., hydrogen peroxide (H2O2), hydroxyl radicals (•OH), and superoxide anions (O2•−). CH-NPs (400 mg L−1) decreased MDA, H2O2, •OH, and O2•− by 33, 33, 40, and 48%, respectively, compared to the unsprayed plants. We hypothesize that CH-NPs increase the efficiency of banana plants in the face of cold stress by reducing the accumulation of reactive oxygen species and, in consequence, the degree of oxidative stress. The accumulation of osmoprotectants (soluble carbohydrates, proline, and amino acids) contributed to enhancing the cold stress tolerance in the banana plants. Foliar application of CH-NPs can be used as a sustainable and economically feasible approach to achieving cold stress tolerance. [ABSTRACT FROM AUTHOR]

Avocado (Persea americana Mill.) is an important fruit crop commercially grown in tropical and subtropical regions. Despite the importance of avocado, there is relatively little available genomic information regarding this fruit species. In this study, we functionally annotated the full-length avocado transcriptome sequence based on single-molecule real-time sequencing technology, and predicted the coding sequences (CDSs), transcription factors (TFs), and long non-coding RNA (lncRNA) sequences. Moreover, 76,777 simple sequence repeat (SSR) loci detected among the 42,096 SSR-containing transcript sequences were used to develop 149,733 expressed sequence tag (EST)-SSR markers. A subset of 100 EST-SSR markers was randomly chosen for an analysis that detected 15 polymorphicEST-SSR markers, with an average polymorphism information content of 0.45. These 15markers were able to clearly and effectively characterize46 avocado accessions based on geographical origin. In summary, our study is the first to generate a full-length transcriptome sequence and develop and analyze a set of EST-SSR markers in avocado. The application of third-generation sequencing techniques for developing SSR markers is a potentially powerful tool for genetic studies. [ABSTRACT FROM AUTHOR]

The growth, development, and production of banana plants are constrained by multiple abiotic stressors. However, it remains elusive for the tolerance mechanisms of banana responding to multiple abiotic stresses. In this study, we found that Fen Jiao (FJ) was more tolerant to osmotic, cold, and salt stresses than BaXi Jiao (BX) by phenotypic and physiological analyses. Comparative transcriptomic analyses highlighted stress tolerance genes that either specifically regulated in FJ or changed more than twofold in FJ relative to BX after treatments. In total, 933, 1644, and 133 stress tolerance genes were identified after osmotic, cold, and salt treatments, respectively. Further integrated analyses found that 30 tolerance genes, including transcription factor, heat shock protein, and E3 ubiquitin protein ligase, could be commonly regulated by osmotic, cold, and salt stresses. Finally, ABA and ROS signaling networks were found to be more active in FJ than in BX under osmotic, cold, and salt treatments, which may contribute to the strong stress tolerances of FJ. Together, this study provides new insights into the tolerance mechanism of banana responding to multiple stresses, thus leading to potential applications in the genetic improvement of multiple abiotic stress tolerances in banana. [ABSTRACT FROM AUTHOR]