Fruit load and elevation affect ethylene biosynthesis and action in apple fruit (Malus domestica L. Borkh) during development, maturation and ripening

Abstract

The influence of internal and external factors such as tree fruit load and elevation on ethylene biosynthesis and action was assessed during apple fruit development and ripening. Ethylene biosynthesis, as well as transcript accumulation of the hormone biosynthetic enzymes (MdACS1 and MdACO1), receptors (MdETR1 and MdERS1) and an element of the transduction pathway (MdCTR1), were evaluated in apples borne by trees with high (HL) and low (LL) fruit load. Orchards were located in two localities differing in elevation and season day degree sum. These parameters significantly affected the date of bloom and commercial harvest, and the length of the fruit developmental cycle. Trees from the low elevation (LE) bloomed and the fruit ripened earlier than those from the high elevation (HE), displaying also a shortened fruit developmental cycle. Dynamics of ethylene evolution was apparently not affected by elevation. The onset of ethylene evolution started 130 days after bloom (DAB) at both elevations. During early ripening, fruits from LL trees produced significantly more ethylene than those from HL trees. Expression analysis of MdACS1, MdACO1 and MdERS1 indicated that the transcript accumulation well correlated with ethylene evolution. MdCTR1 was expressed at constant level throughout fruit growth and development up to 130 DAB, thereafter, the transcript accumulation decreased up to commercial harvest, concurrently with the onset of ethylene evolution.

Ethylene and preharvest drop: the effect of AVG and NAA on fruit abscission in apple (Malus domestica L. Borkh)

“…Transcript accumulation of genes under investigation MdACS1 (U89156), MdACO1 (AB030859), MdETR1 (AF032448), MdERS1 (AY083169) and MdCTR1 (AY670703) was evaluated with specific primers, as reported by Dal Cin et al (2007b), in 25 ll reactions using 0.025 U ll -1 of AmpliTaq Gold (Applied Biosystem) with a Gene Amp PCR system 9700 (Applied Biosystems, Branchburg, NJ). For each reaction a set of a different number of cycles ranging between 20 and 35 was tested to choose those corresponding to the exponential phase.…”

Distribution of <i>MdACS3</i> null alleles in apple (<i>Malus</i> × <i>domestica</i> Borkh.) and its relevance to the fruit ripening characters

“…Given the fact that MdACS3a functions initiate a burst of ethylene production by MdACS1 , the ethylene burst in these cultivars with MdACS3a -null genotypes may be influenced. On the other hand, fruit maturation signal(s) and ambient temperature at the onset of ripening are also known to greatly influence ethylene production (Dal Cin et al 2007, Kubo et al 2009). Eventually early- and middle-maturing cultivars may easily enter the system 2 stage, regardless of their MdACS3a allelotypes (Wang et al 2007).…”

Quality attributes during maturation of ‘Golden Delicious’ and ‘Red Delicious’ apples grown in two geographical regions with different environmental conditions

“…Apple quality characteristics may be affected by factors such as environmental conditions (Dal Cin et al, 2007;Timilsina and Tripathi, 2019), which may also modify the blooming time and maturation rate of the fruit (Dhanaraj et al, 1986;Guédon and Legave, 2008). Among the environmental characteristics that can vary between WA and CHIH include temperature, solar radiation, and photoperiod, which are defined in part by the altitude and latitude of the zones (Drogoudi and Pantelidis, 2011;Jin et al, 2017;Alessandrini et al, 2019;Timilsina and Tripathi, 2019).…”

“…The onset of flowering is hastened by temperature in pears, apples, and leguminous species such as chickpea, which is explained by the fulfilment of the heat requirements (Keatinge et al, 1998;Guédon and Legave, 2008;Kanchan and Bhatia, 2014). The time span in the apple developmental cycle required to reach a given ripening stage seems to be longer in high altitude zones, probably due to a delay in ethylene biosynthesis (Dhanaraj et al, 1986;Danesin et al, 2004;Dal Cin et al, 2007). The ripening rate may be affected by the photoperiod; according to Keatinge et al (1998), temperate leguminous species matured earlier in zones with more extended photoperiod.…”