HbNIN2, a cytosolic alkaline/neutral-invertase, is responsible for sucrose catabolism in rubber-producing laticifers of @entity15543 ( XXXX ).

@entity71483 @entity526 @entity15543
UNASSIGNED: In @entity15543 , an alkaline/neutral invertase (A/N- @entity71483 ) is responsible for sucrose catabolism in latex (essentially the cytoplasm of rubber-producing laticifers, the source of natural rubber) and implicated in rubber yield. However, neither the gene encoding this enzyme nor its molecular and biochemical properties have been well documented. Three Hevea A/N- @entity71483 genes, namely HbNIN1, 2 and 3, were first cloned and characterized in planta and in @entity526 . Cellular localizations of HbNIN2 mRNA and protein were probed. From latex, active A/N- @entity71483 proteins were purified, identified, and explored for enzymatic properties. HbNIN2 was identified as the major A/N- @entity71483 gene functioning in latex based on its functionality in @entity526 , its latex-predominant expression, the conspicuous localization of its mRNA and protein in the laticifers, and its expressional correlation with rubber yield. An active A/N- @entity71483 protein was partially purified from latex, and determined as HbNIN2. The enhancement of HbNIN2 enzymatic activity by pyridoxal is peculiar to A/N-Invs in other plants. We conclude that HbNIN2, a cytosolic A/N- @entity71483 , is responsible for sucrose catabolism in rubber laticifers. The results contribute to the studies of sucrose catabolism in plants as a whole and natural rubber synthesis in particular.
