Sugar and Hormone Dynamics and the Expression Profiles of SUT/SUC and SWEET Sugar Transporters during Flower Development in <i>Petunia axillaris</i>
Junaid Iftikhar,
Meiling Lyu,
Zhuoyi Liu,
Nasir Mehmood,
Nigarish Munir,
Mohamed A. A. Ahmed,
Wajjiha Batool,
Mehtab Muhammad Aslam,
Yuan Yuan,
Binghua Wu
Affiliations
Junaid Iftikhar
College of Horticulture and the Fujian Provincial Key Laboratory of Plant Functional Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Meiling Lyu
College of Horticulture and the Fujian Provincial Key Laboratory of Plant Functional Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Zhuoyi Liu
College of Horticulture and the Fujian Provincial Key Laboratory of Plant Functional Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Nasir Mehmood
College of Horticulture and the Fujian Provincial Key Laboratory of Plant Functional Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Nigarish Munir
Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Mohamed A. A. Ahmed
College of Horticulture and the Fujian Provincial Key Laboratory of Plant Functional Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Wajjiha Batool
College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Mehtab Muhammad Aslam
College of life Sciences, Joint International Research Laboratory of Water and Nutrition in Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Yuan Yuan
College of Horticulture and the Fujian Provincial Key Laboratory of Plant Functional Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Binghua Wu
College of Horticulture and the Fujian Provincial Key Laboratory of Plant Functional Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Flowering is the first committed step of plant sexual reproduction. While the developing flower is a strong sink requiring large quantity of sugars from photosynthetic source tissues, this process is under-temper-spatially controlled via hormone signaling pathway and nutrient availability. Sugar transporters SUT/SUC and SWEET mediate sugars movement across membranes and play a significant role in various physiological processes, including reproductive organ development. In Petunia axillaris, a model ornamental plant, 5 SUT/SUC and 36 SWEET genes are identified in the current version of the genome. Analysis of their gene structure and chromosomal locations reveal that SWEET family is moderately expanded. Most of the transporter genes are abundantly expressed in the flower than in other organs. During the five flower developmental stages, transcript levels of PaSUT1, PaSUT3, PaSWEET13c, PaSWEET9a, PaSWEET1d, PaSWEET5a and PaSWEET14a increase with the maturation of the flower and reach their maximum in the fully open flowers. PaSWEET9c, the nectar-specific PhNEC1 orthologous, is expressed in matured and fully opened flowers. Moreover, determination of sugar concentrations and phytohormone dynamics in flowers at the five developmental stages shows that glucose is the predominant form of sugar in young flowers at the early stage but depletes at the later stage, whereas sucrose accumulates only in maturated flowers prior to the corolla opening. On the other hand, GA3 content and to a less extent IAA and zeatin decreases with the flower development; however, JA, SA and ABA display a remarkable peak at mid- or later flower developmental stage.
