Identification of proteins associated with reducing regrowth and with the longevity of cane fields

Abstract

Budding axillary buds are crucial for the establishment and longevity of commercial and industrial sugarcane varieties (Saccharum spp.). Increasing the longevity of sugarcane varieties beyond the fifth or sixth cutting stage without decreasing agricultural productivity is a promising economic outlook for producers. Identifying the factors that limit the longevity of cane fields can be an alternative to bypass the regrowth limits of axillary buds. This study aimed to evaluate the bud sprouting rates of axillary buds of the variety RB867515 from the first to the fifth cut and to identify the prevalent proteins in the axillary buds of sugarcanes of the first, third, and fifth cutting stages. The ultra-performance liquid chromatography in tandem with quadrupole-time-of-flight electrospray ionization from one-dimensional gel electrophoresis (1DE-UPLC-ESI-QTOF) mass spectrometry approach was used to obtain the proteome of the axillary buds in the first, third, and fifth cuts. The sprouting rate was evaluated using a caliper and considered positive when the budding of the axillary buds increased by at least 6 mm. Proteins were extracted in biological triplicate for each cutting stage, and the identification of proteins, based on acquired MS/MS spectra, was performed using the Mascot tool from Matrix Science against Viridiplantae within the SwissProt/UniProtKB and databases UP7305_Z_mays in Uniprot. The budding rate in the axillary buds of the first cut was 69.8%. In contrast, the germination rate of the axillary buds of the third cutting was 36.4%. Exclusive proteins were identified in the first, third, and fifth cutting stages, and a 49.3% reduction in the number of proteins was observed in the third cut compared to the first one. Absence of essential proteins/enzymes involved in i) carbohydrate metabolism, ii) folding and degradation of proteins (proteolytic functions), iii) 40S and 60S ribosomal subunits, and iv) proteins involved in biotic and abiotic stresses, are factors that may limit the longevity of cane fields from the third cut before the fifth or sixth cutting stage, when productivity in the field became economically unfeasible