MaDREB1F confers cold and drought stress resistance through common regulation of hormone synthesis and protectant metabolite contents in banana

Adverse environmental factors severely affect crop productivity.Improving crop resistance to multiple stressors is an important breeding goal.Although CBFs/DREB1s extensively participate in plant resistance to abiotic stress,the common mechanism underlying CBFs/DREB1s that mediate resistance to multiple stressors remains unclear.Here,we show the common mechanism for MaDREB1F conferring cold and drought stress resistance in banana.MaDREB1F encodes a dehydration-responsive element binding protein(DREB)transcription factor with nuclear localization and transcriptional activity.MaDREB1F expression is significantly induced after cold,osmotic,and salt treatments.MaDREB1F overexpression increases banana resistance to cold and drought stress by common modulation of the protectant metabolite levels of soluble sugar and proline,activating the antioxidant system,and promoting jasmonate and ethylene syntheses.Transcriptomic analysis shows that MaDREB1F activates or alleviates the repression of jasmonate and ethylene biosynthetic genes under cold and drought conditions.Moreover,MaDREB1F directly activates the promoter activities of MaAOC4 and MaACO_(2)0 for jasmonate and ethylene syntheses,respectively,under cold and drought conditions.MaDREB1F also targets the MaERF11 promoter to activate MaACO_(2)0 expression for ethylene synthesis under drought stress.Together,our findings offer new insight into the common mechanism underlying CBF/DREB1-mediated cold and drought stress resistance,which has substantial implications for engineering cold-and drought-tolerant crops.

Chromosome-scale genome assembly provides insights into the evolution and flavor synthesis of passion fruit (Passiflora edulis Sims)

Passion fruit(Passiflora edulis Sims)is an economically valuable fruit that is cultivated in tropical and subtropical regions of the world.Here,we report an~1341.7Mb chromosome-scale genome assembly of passion fruit,with 98.91%(~1327.18Mb)of the assembly assigned to nine pseudochromosomes.The genome includes 23,171 protein-coding genes,and most of the assembled sequences are repetitive sequences,with long-terminal repeats(LTRs)being the most abundant.Phylogenetic analysis revealed that passion fruit diverged after Brassicaceae and before Euphorbiaceae.Ks analysis showed that two whole-genome duplication events occurred in passion fruit at 65 MYA and 12 MYA,which may have contributed to its large genome size.An integrated analysis of genomic,transcriptomic,and metabolomic data showed that‘alpha-linolenic acid metabolism’,‘metabolic pathways’,and‘secondary metabolic pathways’were the main pathways involved in the synthesis of important volatile organic compounds(VOCs)in passion fruit,and this analysis identified some candidate genes,including GDP-fucose Transporter 1-like,Tetratricopeptide repeat protein 33,protein NETWORKED 4B isoform X1,and Golgin Subfamily A member 6-like protein 22.In addition,we identified 13 important gene families in fatty acid pathways and eight important gene families in terpene pathways.Gene family analysis showed that the ACX,ADH,ALDH,and HPL gene families,especially ACX13/14/15/20,ADH13/26/33,ALDH1/4/21,and HPL4/6,were the key genes for ester synthesis,while the TPS gene family,especially PeTPS2/3/4/24,was the key gene family for terpene synthesis.This work provides insights into genome evolution and flavor trait biology and offers valuable resources for the improved cultivation of passion fruit.

Cultivation and Management Technologies for New Banana Cultivar ‘Refen 1’(Musa Spp. ABB,Pisang Awak Subgroup)

Banana is one of the most important crops in tropical and subtropical regions of China. Fenjiao( Musa Spp. ABB,Pisang Awak subgroup) has been grown by small scale famers because of its stable market price and better sugar-acid blend. However,the traditional Fenjiao variety is susceptible to banana Fusarium wilt,has a high plant height( over 5. 0 m),and farmers lack large-scale planting techniques.Based on the traditional Fenjiao variety,we selected‘Refen 1’variety through mutagenesis technology,which has low temperature resistance,suitable to marginal soils and relatively low plant height( 3. 2-4. 0 m). This paper mainly introduces the major techniques of propagation,cultivation,and post-harvest stages of‘Refen 1’banana,including the selection of explant materials,treatment,disinfection,initial culture,nursery hardening of in vitro-produced banana plants,and transplant of tissue culture seedlings. The major points of the cultivation technology include banana plantation selection and preparation,planting methods,irrigation and fertilizer management,pruning and retaining,and prevention and control of plant diseases and insect pests.

Research progress on the MYB transcription factors in tropical fruit

Tropical fruits,such as bananas,passion fruit,mangoes,and lychees,are rich in vitamins,flavonoids and non-flavonoid phenols,and are the healthiest way to intake bioactive compounds in one's daily diet.Coupled with their unique taste,tropical fruits are becoming more increasingly popular.The production of bananas is second only after grapes,while other tropical fruit are limited by the planting environment,resulting in a relatively low planting area and yield.With the improvement in breeding technology and planting technology,the development of tropical fruit crops will have broad prospects.MYB plays a major regulatory role in several biological processes,including growth and development of plants,quality formation,and stress resistance.There is a comparatively junior level of research on tropical fruit crops compared to grain fruit and model plants.Despite the progress that has been made in the development of molecular biology methods that can transform the genetic makeup of tropical fruit crops,the functional understanding of the multiple MYB genes is still in its initial stages.This paper aims to review the current status of the research on the development of these genes and their prospects.It is expected to provide a reference for the study of MYB transcription factors in tropical fruit crops and to provide new ideas for the functional resolution of MYB transcription factors in different biological processes.