Table 1.

Significant BTPC expression correlates with elevated intracellular concentrations of L-malate

Species/ Tissue	Developmental stage	Estimated malate concentration (mM)	Reference
Castor endosperm	stage III*	80	Wheeler et al., 2016
	stage IV*	80
	stage V*	80
	stages VI-VIII	80
	stages IX-X	30
Cotton embryo	5 DPA	50	Li et al., 2010
	10 DPA*	70
	15 DPA	35
	20 DPA	20
	25 DPA	10
Soybean embryo	stage R5.5*	60	Wheeler et al., 2016
	stage R6	50
	stage R6.5	25
	stage R7	20
	stage R8	20
Tomato endocarp	10 DPA (immature green)	11–15	Guillet et al., 2002
	20 DPA (immature green)*	13–23	Mounet et al., 2007
	35 DPA (mature green)*	30–35
	45 DPA (red ripe)	5–14
Cucumber endocarp	<11 DAP*	19	Handley et al., 1983
	11 DAP	15
	23 DAP	15
	24–44 DAP	7.5
	45 DAP	11
Grape berry	Pre-ripe, -30 d	100	Diakou et al., 1997
	Pre-ripe, -5 d*	150
	Ripe, 0 d	93
	Post-ripe, +10 d	63
	Post-ripe, +20 d	37

Developmental stages having maximal BTPC expression (Figs 3 and 5) are indicated with bold font and an asterisk. Intracellular malate concentrations were estimated from data provided in the cited publications by assuming that 1 gFW is equivalent to 0.1 gDW and that 1 gFW is equivalent to 1 mL of aqueous volume. Castor and soybean seed developmental stages are as previously described (Blonde and Plaxton, 2003; Wheeler et al., 2016).